Updated 1 July 2026 · 4-minute read
Step 1: Decide which type of key your car uses
Before you price anything, work out which kind of key your car has. There are three broad categories:
- Plain metal flip key. A separate key blade that folds into a small plastic remote. Common in 2000s and early 2010s cars (Fiesta 2002–2017, Corsa D/E, Golf MK5/6, Astra J, Focus MK2/3, Polo 9N/6R). Cheapest to replace.
- Integrated remote key (sometimes called "flip remote" or "smart key"). Key blade and buttons in one moulded unit. Common from 2010 onwards (Fiesta 2017+, Polo 6C/ AW, Golf MK7, Astra K, i20, Clio V, Ibiza).
- Smart key / proximity key (keyless go). Key stays in your pocket. The car detects it. Push-button start. Common in 2017+ cars (VW Golf MK7.5+, Audi A4 B9+, BMW 1-Series F40, Mercedes A-Class W177, Ford Kuga, Toyota CH-R).
Check your owner's manual or the original key fob. If you have a flip blade, it's category 1 or 2. If there's no blade at all, it's category 3.
Step 2: OEM vs aftermarket — which is better?
The honest answer: both work identically. Aftermarket blanks from reputable suppliers (Xhorse, KeyDIY, KD, XTool) are made in the same Chinese factories as OEM, with the same transponder chips and circuit boards. The differences are minor:
- OEM: car badge stamped on the case, premium finish, full warranty from the dealer. Costs more (often 30–60% more) for essentially the same electronics.
- Aftermarket: generic or no badge. Same internals, slightly less refined case finish. Costs less.
Insurers don't care which you have — they care that the key works. Police don't care either. Your car doesn't know the difference after coding. We typically use OEM where the price is competitive and aftermarket for premium keys where OEM is prohibitively expensive (BMW display key, Range Rover).
Step 3: Buy for the car, not the spec sheet
Two common traps to avoid:
- Don't buy the cheapest "universal" key off eBay. Many of these are cloned or non-functioning. Spend the extra £20–£40 for a known good blank from a locksmith or reputable supplier.
- Don't pay extra for "all-features" if you don't have them on the original key. If your existing key doesn't have keyless-go, a smart-key spare won't add that feature. Coding matches what the car has, not what the fob can theoretically do.
Step 4: Think about where the spare will live
The best spare is the one that's there when you need it. Plan where it goes before you buy.
- At home in a Faraday pouch — keeps the spare safe from relay theft. Don't keep it in a hallway bowl near the front door. Bedroom drawer is much better.
- With a trusted friend or family member — particularly if you live alone or in a flat with a concierge. They can bring it to you.
- Not on the same keyring as your main key — if you lose both, the spare's gone too.
Step 5: Choose the right features
Modern keys have a lot of features, and you don't always need them all on a spare:
- Lock / unlock / boot release — standard on virtually all spares. Get this.
- Keyless entry / keyless go — only if your car has it from factory. Otherwise it's not useful.
- Remote start — only on certain Ford, Chrysler and BMW models. Useful in winter.
- Panic alarm — usually a separate button on the fob. Handy to have on the spare.
- Fold-out blade vs non-folding — modern smart keys (proximity) usually don't have a fold-out blade. If you have a comfort-access car, plan for that.
Step 6: Think about the long game
A spare key isn't a one-off purchase. Plan to:
- Replace the spare's battery every 2–3 years (CR2032 or CR2025 — usually £1.50 on eBay).
- Get the spare re-coded if you change the car's body control module (rare but it happens).
- Replace the spare if it gets wet or dropped repeatedly — transponders can fail intermittently before they fail completely.
- If you have a 2-year-old spare that's never been used, test it now. Some transponders drain even when not used.
Step 7: Use a mobile auto locksmith
For North Wales drivers, mobile is the obvious choice:
- No need to drive to a dealer or wait days for an appointment.
- Same equipment as the main dealer (Autel, XTool, ODIS for VAG group).
- Same quality blank and coding — just a different supplier chain.
- 30–60% cheaper than the main dealer, typically.
- Convenient: the locksmith comes to your home or workplace.
Common mistakes to avoid
- Waiting until you've lost the only key — this is the single most expensive mistake. A spare is half the cost of an emergency replacement.
- Buying a "universal" Chinese key off eBay — most don't work or break within months.
- Not testing the spare for years — batteries die even when not used. Test every 6 months.
- Storing the spare in the same place as the main key — defeats the purpose. Keep them apart.
- Skipping the Faraday pouch — the most common relay theft happens at home, when the spare is by the front door. The £5–£10 pouch fixes this.
Special cases
Display key (BMW, Range Rover): if your car has the fancy display key, the spare is usually a regular smart key — a display key spare is £400+. We can code a regular smart-key spare that opens and starts the car fine; you just don't get the LCD screen features.
Push-to-start, blade in key: many modern cars (VW Group, BMW) have a hidden emergency blade. The spare smart key usually includes one. Keep it with the spare.
Commercial vehicles (Transit, Vivaro, Crafter, Sprinter): most have a simple flip key, but newer ones have keyless. Spares are cheaper than for premium cars and quicker to code.
Need help choosing the right spare for your car? Call 07803 473728 with your reg and we'll tell you exactly what fits, what it'll cost, and when we can come.