In my personal opinion, if the cars really are A1, then paying ?3k for a mint valver is par for the course, as finding a mint, straight one with full history and non-glaltic mileage is becoming harder and harder.
However, where I do agree with what you're saying is when people are asking top dollar for a car that doesn't fit the bill! Just because the doors aren't rusting off and the head gasket hasn't gone, it doesn't make the car a minter!