Six thousand pounds, needs to survive two MOTs, what do you actually check on a UK used car?

For your specific worry about the belt: find out whether that engine has a belt or a chain before you shortlist anything, because it changes the sums entirely. If it is a belt, the only thing that counts is a dated invoice from a garage with the mileage on it. A seller saying it was done is not evidence, and a stamp in a book without a receipt is barely better. On a six thousand pound car, an unproven belt is a bill you should assume you are paying, so knock it off what you offer or walk away.

Pull the MOT history online from the reg before you even drive out to see it. It is free, it takes a minute, and it tells you more than the seller will. What you are reading for is not the passes, it is the advisories and the mileage line. Advisories that repeat year after year mean nothing has ever been fixed, mileage that jumps around means the recorded readings are inconsistent, and a car with a gap in its testing history was sitting somewhere for a reason.

I will disagree slightly with paying the dealer premium. On a six grand motorway car, what actually protects you is a proper pre-purchase inspection, not a warranty, and one of those costs a small fraction of the price gap between private and trade. I buy privately, I book an inspection on anything I am serious about, and the inspector has twice found things that saved me thousands. A three month warranty on a fifteen year old car covers a narrow list of parts and nothing you actually fear.

Buying from a trader rather than privately does give you rights you simply do not get from a private seller, and on a car at your budget that is worth real money if something goes wrong in the first few months. Privately, the bar is essentially that the car is as described, and that is a much harder thing to argue about afterwards. I have bought both ways. If you are confident enough to inspect properly or you are paying for an inspection, private is cheaper. If you are not, the dealer margin is buying you something. Worth checking the current consumer rules yourself or with Citizens Advice rather than taking my word for the detail.

Motorway miles are your friend, so do not be scared of a high number on a well serviced car. Look underneath at the sills and the rear arches, look for a cold start rather than an engine that is already warm when you arrive, and get the belt receipt. Everything else is negotiable.

I skipped a history check to save the cost of a takeaway and bought a car with outstanding finance on it. That was a genuinely frightening few weeks and it was entirely avoidable. Run the reg through a proper history check, look for finance, write-off markers and a mileage discrepancy, and match the numbers on the paperwork against the numbers on the car itself. It is the cheapest hour of the whole process.