Sean Hamilton's hands replacing a multi-point gearbox mechanism in the edge of a white uPVC door, the stainless locking strip and hooks visible, warm amber light catching the metalwork

uPVC door lock replacement

uPVC door lock replacement: what's involved, and what it should cost

Wolverhampton, Stafford and Cannock. Honest diagnosis before a single part is fitted.

"uPVC door lock" means three different things, and which one you need decides whether this is a £90 job or a £150 one. It's the barrel (the cylinder with the keyhole), the gearbox (the mechanism down the edge of the door that throws the hooks), or the handle. Most people who think they need a whole new mechanism actually need a barrel swap, and plenty get quoted for the expensive one when the cheap one would have fixed it. This page shows you how to tell which is which, what each costs, and how to avoid being oversold. Diagnosis on the doorstep is always free, there's no call-out fee, and you only pay for the part that's actually failed.

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The three things people mean by "uPVC door lock"

When someone rings me to "replace the lock on my uPVC door", they could mean any of three separate parts, and the difference is the difference between a quick cheap fix and a bigger job. Knowing which one you're talking about is half the battle:

  • The barrel (euro cylinder). The part with the keyhole, sitting in the strip-edge of the door. This is what you change for lost keys, a house move, or a security upgrade. Held in by a single screw. From £90 fitted.
  • The gearbox (multi-point mechanism). The long metal strip down the edge of the door with the hooks, rollers and bolts, driven by a central gearbox when you lift the handle. This is what fails when the handle goes floppy or the hooks won't throw. From £145 fitted.
  • The handle. The lever set on the face of the door. Sometimes the handle itself snaps or the spring fails while the mechanism behind it is fine. A handle-only swap is the cheapest of the three.
Three uPVC door lock components laid out on a dark workbench under warm amber light, each labelled: a brass euro cylinder labelled THE BARREL (CYLINDER), a long stainless multi-point locking strip with hooks and a central gearbox labelled THE GEARBOX (MECHANISM), and a chrome lever handle set labelled THE HANDLE.
The three parts of a uPVC door lock, and they fail independently. Most "my lock's gone" calls turn out to be the barrel, the cheapest of the three. The gearbox is the one people fear they need, and only sometimes do.

Barrel, gearbox or full mechanism: which do you need?

You can usually narrow it down in thirty seconds with the door open. Work down these three and you'll know whether you're looking at a cheap cylinder swap or a bigger mechanism job before anyone quotes you.

  1. Key turns and the door locks, but you want a new lock: it is the BARREL

    Lost a key, moved house, want an anti-snap upgrade, or the key is getting stiff in the cylinder? That is a euro cylinder (barrel) swap and nothing more. The mechanism stays, the handle stays, only the part with the keyhole changes. From £90 fitted for a standard cylinder, or from £130 for a TS007 3-star anti-snap one.

  2. Handle has gone floppy or the hooks will not throw: it is the GEARBOX

    If you lift the handle and it feels loose or sloppy, or the multi-point hooks do not shoot out properly when you lift it, the gearbox inside the mechanism has worn or failed. That is a multi-point gearbox replacement, from £145 fitted. A new barrel will not fix this, and anyone selling you one for a gearbox fault has not diagnosed it properly.

  3. Not sure, or it is doing something odd: get it diagnosed free first

    Sometimes it is alignment (the door has dropped and the hooks are catching the keeps), which is no new parts at all. Sometimes it is both the cylinder and the gearbox. I diagnose it on the doorstep for free before quoting, so you only pay for the part that has actually failed. If you want to narrow it down yourself first, my door will not lock page walks through it.

How much does a uPVC door lock replacement cost?

Here are the floor prices for each part, so you can see at a glance what your job should land at. All include my attendance and labour, with no separate call-out fee and no VAT added. The part of the job that earns the money is the diagnosis: getting the right answer on which part has failed, so you don't pay for the wrong one.

  • Euro cylinder (barrel) swap, standard cylinder fitted from £90
  • TS007 3-star anti-snap cylinder upgrade, fitted from £130
  • Multi-point gearbox (mechanism) replacement, fitted from £145
  • Handle-only replacement quoted on the day
  • Door drop / alignment adjustment (no new parts) from £90

Gearbox prices vary a little by brand (Fullex, GU, Mila and Lockmaster differ in cost), which I confirm on the phone once I know what's on your door. See the full price list and what each one covers →

Getting the cylinder size right (don't buy the wrong barrel)

If you're tempted to buy a euro cylinder online and fit it yourself, the one thing that catches almost everyone out is the measurement. A euro cylinder is measured from the centre fixing screw outwards to each face of the door, not end to end, and it's almost never symmetrical. You end up with two figures like 40/50. Get it wrong and one of two things happens: too long and it stands proud of the handle (which looks wrong and, more importantly, gives an attacker something to grip and snap), or too short and it won't reach the cam to turn the lock at all.

There's a full measuring guide with a diagram on my euro cylinder size page. If you'd rather not measure, send me a photo of the door edge with a tape measure laid across the cylinder and I'll work out the exact size you need. It's a frequent reason people end up calling me out twice: once for the wrong part they bought, once to fit the right one.

What actually happens on the doorstep

If you ring me with a uPVC door lock problem, here's how it goes. I take the postcode, the door type, and whatever you can tell me about the symptom (key won't turn, handle floppy, door stiff to lock). I give you a price band on the phone with the likely options. I arrive in the window I gave you, usually within a couple of hours for same-day, or a planned slot if you'd rather book ahead.

On the doorstep I diagnose it free before anything is fitted. A cylinder swap is quick: out with the single fixing screw, measure the lengths front and rear of the cam, fit the matching new cylinder from the van, hand you new keys, test the door several times from both sides. A gearbox replacement takes longer: the mechanism comes out of the edge of the door, the replacement is matched to the same backset and centre measurements, and the handles and keeps are reset so it all lines up. I carry the common cylinders and the popular gearbox brands in the van, so the large majority of jobs are finished the same visit. You get an itemised receipt showing the labour and the exact part fitted.

The overselling trap, and how to avoid it

The most common way people overpay on a uPVC door is being sold a full multi-point mechanism when a barrel swap, or even a free alignment tweak, would have fixed it. A stiff door is very often a dropped slab catching the keeps, not a failed mechanism. A key that's getting harder to turn is usually a worn cylinder, not a failed gearbox. Both of those are cheap. A whole mechanism is not.

What an honest locksmith will tell you before fitting anything

Before you agree to a "full mechanism replacement" on a uPVC door, ask the locksmith to show you exactly what has failed. If the handle lifts firmly and the hooks throw smoothly with the door open, the mechanism is fine and you're being sold the wrong part. A worn cylinder is from £90 fitted. A genuine gearbox failure is from £145 fitted. The two are not interchangeable, and a fair locksmith will diagnose which it is, for free, before quoting. It works the other way too: a cheap barrel fitted to a door whose gearbox is actually the problem just leaves you calling someone out again.

Recent uPVC lock replacements in Wolverhampton, Stafford and Cannock

Three recent jobs: one where a national number quoted a full mechanism and a barrel fixed it, one where it genuinely was the gearbox, and one wrong-size barrel bought online. Real prices on the receipt, sat next to what was quoted elsewhere. Customer details lightly anonymised at their request.

  1. Tuesday 26 May 2026 at 9.00am · Wolverhampton

    Mr Bennett, Wolverhampton

    uPVC front door in WV4 getting stiff to lock, needing a proper shove to get the key over. A national locksmith number had been out and quoted a "full multi-point mechanism replacement" at £265, telling him the whole lock was failing.

    A national number quoted the customer £265
    Paid to me £95

    It was not the mechanism at all. The euro cylinder was worn and the door had dropped a touch so the hooks were catching. I swapped the cylinder, adjusted the keeps and hinges to bring the door back into line, and it locked with one finger again. From £90 for the cylinder. Saved him £170 and a mechanism he did not need.

  2. Friday 29 May 2026 at 4.30pm · Stafford

    Ms Fielding, Stafford

    Handle on a uPVC back door in ST17 had gone completely floppy and would not lift to throw the hooks, so the door could only be locked on the latch. This one genuinely was the mechanism: the Fullex gearbox inside had stripped.

    A national number quoted the customer n/a
    Paid to me £155

    Replaced the full Fullex multi-point gearbox like-for-like, matched to the same backset and centre measurements, from £145. Tested it twenty times from both sides before I left. This is the job people are scared they have when it is usually just a barrel, but when it really is the gearbox, this is the honest fix and it will outlast a patch.

  3. Saturday 23 May 2026 at 11.30am · Cannock

    Mr Whitehouse, Cannock

    Bought a euro cylinder online to save money on a WS12 uPVC door, but measured it end to end instead of from the centre screw. The barrel he received stuck out past the handle and would not turn smoothly, and a protruding cylinder is itself a snap risk.

    A national number quoted the customer n/a
    Paid to me £130

    Measured the door properly (40/45 from the centre screw), fitted a correct-length TS007 3-star anti-snap cylinder that sits flush, and showed him how to read the sizing so it never happens again. The £12 he saved buying online would have cost him a second part and a snap-vulnerable door. From £130 fitted for the anti-snap.

Typical UK locksmith pricing for this work is covered by the Master Locksmiths Association's price guidance. My from-prices are £90 for a cylinder swap, £130 for a TS007 3-star anti-snap cylinder, and £145 for a full multi-point gearbox.

Prices

From-prices for uPVC door lock replacement

The figures below are floor prices for the most common uPVC door lock jobs. They include attendance and labour with no separate call-out fee. The full price list with covers and affects sits on the dedicated pricing page.

  • Euro cylinder (barrel) swap, standard cylinder fitted from £90
  • TS007 3-star anti-snap cylinder, fitted from £130
  • Multi-point gearbox (Fullex / GU / Mila / Lockmaster), fitted from £145
  • Handle-only replacement quoted on the day

No VAT added on top. No call-out fee. Diagnosis on the doorstep is free, and you only pay for the part that's actually failed. See the full price list and what each one covers →

The three replaceable parts of a uPVC door lock labelled on a dark workbench: the barrel (euro cylinder), the gearbox (multi-point mechanism), and the handle.
Sean Hamilton from Lockerfella, in the branded Lockerfella t-shirt, handing a fresh set of keys to a smiling young woman customer at her uPVC composite front door on a sunny south Staffordshire afternoon

About the locksmith

The locksmith answering your call

I'm Sean Hamilton. I run Lockerfella as a one-man-band out of Brewood. If your uPVC door has stopped locking, the key won't turn, or the handle has gone floppy, send me a photo or ring me with the symptom and your postcode. I'll diagnose it free before fitting anything, tell you honestly whether it's a barrel, a gearbox or just an alignment tweak, and the price on the phone is the price on the receipt. No call-out fee. No selling you a mechanism you don't need.

  • 30+ years fascinated by locks. I've been picking, stripping and studying locks for the love of it for over 30 years. Lockerfella is what happens when a lifelong interest in how locks work becomes the day job.
  • Trained and certified. Certificate of Locksmith Skills from A'Jam Locksmiths covering cylinder, mortice, padlock, wafer and euro lock picking, plus re-keying and mortice bypassing.
  • Standard DBS checked, £1M insured, 12 months workmanship guarantee. Redacted DBS and insurance certificates are published on the About page, with originals available to view in person before work starts.
  • One man, one van, one phone number. The phone rings on me directly. No call centre. No third-party fitter. If I quote you a price, that's the price you pay.

Read the full About page See the brands I fit

Common questions about uPVC door lock replacement

Straight answers on cost, barrel vs gearbox, how long it takes, doing it yourself, cylinder sizing, and whether you really need the whole mechanism.

How much does it cost to replace a uPVC door lock?

It depends which part actually needs replacing, because "uPVC door lock" covers three different things at three different prices. A new euro cylinder (the barrel, the part with the keyhole) is from £90 fitted, labour and a standard cylinder included. A TS007 3-star anti-snap cylinder is from £130 fitted. A full multi-point gearbox (the long strip down the edge of the door with the hooks and rollers) is from £145 fitted. The honest part of the job is working out which one you actually need, because a lot of people get quoted for the whole mechanism when a barrel swap would have fixed it. Diagnosis on the doorstep is free, no call-out fee, no VAT added.

Can I just replace the barrel, or do I need the whole mechanism?

Most of the time, just the barrel. If your key still turns and throws the bolts but you want a new lock (you have lost a key, moved house, or want an anti-snap upgrade), that is a cylinder swap and nothing more, from £90 fitted. You only need the whole multi-point mechanism if the mechanism itself has failed: the handle has gone floppy, the hooks will not throw when you lift the handle, or something has snapped inside the gearbox. Those are two very different jobs at two very different prices, so the first thing I do on the doorstep is tell you honestly which one it is. If a barrel will fix it, that is what you pay for.

How do I know if it is the barrel or the gearbox?

A quick test: with the door open, lift the handle. If the hooks and bolts shoot out smoothly and the handle feels firm, the mechanism is healthy and any problem is with the cylinder (the key side). If you lift the handle and it feels loose, sloppy, or the hooks do not come out properly, that points at the gearbox inside the mechanism. If the key will not turn but the handle works fine, it is usually the cylinder. If the handle will not lift but the key is fine, it is usually the gearbox. It is not always clean-cut, which is why I diagnose it free before quoting. There is a fuller walk-through on my door will not lock page if you want to narrow it down before you call.

How long does a uPVC door lock replacement take?

A euro cylinder swap is quick, usually 15 to 20 minutes on the doorstep including testing the new keys both sides and cleaning up. A full multi-point gearbox replacement takes longer, anywhere from 30 minutes to a bit over an hour, because the mechanism has to come out of the edge of the door, the replacement has to be matched to the same backset and centre measurements, and sometimes the gearbox is a slightly different pattern that needs adapting. Either way I carry the common cylinders and the popular gearbox brands (Fullex, GU, Mila, Lockmaster) in the van, so most jobs are done same-visit rather than a return trip.

Can I replace a uPVC door lock myself?

A euro cylinder is the one part a confident DIYer can sometimes manage, as long as you measure it correctly. There is one fixing screw, usually under the handle on the edge of the door, and the cylinder slides out once the key is turned to line the cam up. The two things that catch people out are buying the wrong size (measured end to end instead of from the centre screw, so it sits proud or recessed) and ending up with a cylinder that sticks out past the handle, which is itself a snap risk. A multi-point gearbox is a different matter and not a DIY job: matching the backset, centre and handle pattern is fiddly, and forcing the wrong one in usually makes it worse. If in doubt, send me a photo first.

What size euro cylinder do I need?

You measure it from the centre fixing screw outwards to each face of the door, not end to end, because a euro cylinder is almost never symmetrical. You end up with two figures, for example 40/50, where 40 is the distance from the centre screw to the outside and 50 to the inside. Getting it right matters: too long and it stands proud of the handle, which both looks wrong and gives an attacker something to grip and snap; too short and it will not reach the cam to turn the lock. I have a full measuring guide with a diagram on my euro cylinder size page. If you would rather not measure, send me a photo of the door edge with a tape measure across the cylinder and I will work it out.

Do you have to replace the whole multipoint mechanism?

Only if the mechanism is the part that has failed. If a single component has gone, the gearbox in the centre for instance, it is sometimes possible to replace just that part rather than the entire strip, which is cheaper. If the whole mechanism is worn, seized or an obsolete pattern, a full replacement from £145 fitted is the sensible fix and will outlast a patch. What you should not be doing is replacing a working mechanism because a cylinder needed changing, or vice versa. I will show you exactly what has failed before anything gets ordered or fitted, so you only pay for the part that needs it.

Ready when you are

uPVC door playing up? Get an honest diagnosis first.

Send me a photo or tell me the symptom and your postcode. I'll tell you whether it's a barrel, a gearbox or just alignment, and what it should cost, before anything is fitted. No call-out fee. No deposit. No surprises.

Page last reviewed: . Reviewed by Sean Hamilton, the locksmith behind Lockerfella, under our editorial standards.

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