I sold an old car a few years ago for �400. The man who bought it came back the following day (less than 24 hours) wanting his money back as he thought that the brakes were 'dodgy.' I refused as the car was sold as seen, and I hadn't had a problem with the brakes anyway. He turned quite nasty and threatening, but I refused to take the car back. When he left, I was so shaken that I called the police - just because I was concerned that he knew where I lived, and they noted my call. Anyway (getting to the point!) a few weeks later, the Serious Crime Squad turned up at my house in connection with an armed robbery that had involved the car and had taken place a few hours after I had sold it. So, the moral of this story is (!) if I would have accepted the car back, I wouldn't have notified DVLA of a change of owner, I wouldn't have notified the police of my concerns and I could be doing time for a crime I didn't commit! So no, I don't think that he should have taken the car back - buyer beware!