It really depends what you mean by 'not in good condition'. The 2015 Consumer Rights Act covers the purchase of goods and services - including new and used cars - from official dealers. It doesn't apply to private sales. It outlines the fact that vehicles must be of satisfactory quality, fit for purpose and as described. This Act gives you the statutory right to reject a new or used car (or anything else) within 30 days of purchase if your rights have been breached. Cosmetic issues or minor faults aren't valid reasons to reject a vehicle. These sorts of issues should be dealt with under warranty if you have one. You also can’t successfully reject a car for a trivial reason such as a little scratch.

It covers faults that were present - or developing - when you bought it, or it was received in a condition that does not match what you were told. But it'll be up to you to prove that's the case. After 30 days you lose the short-term right to reject. It's much harder to get money back from a private sale, but you've not given us enough detail to get into that.

You also won’t be entitled to anything if you were told about the fault when you bought the car or you inspected the car and should've spotted the problem. Similarly, you don't have rights against the supplier if you caused the fault or the issue is to be expected based on the age of the car (fair wear and tear). So-called fair wear and tear could include things like the brake pads needing to be replaced on a used car.

You can read all about your rights here: www.honestjohn.co.uk/problems-with-a-new-or-used-c...s