Trying to buy a used Cooper

[Blue62]

In the market for a used Cooper, budget @£10k and decided to call a few dealers on the Mini website. Two days ago I made 4 calls to different dealers, had to leave 3 messages, none of which have so far resulted in a call back and had one conversation with a salesman who couldn't answer my questions (previous owners, exact spec) but promised he'd call back. All he did tell me is that prices are fixed centrally on used Coopers so no need to haggle (I don't believe this).

I know that car dealers are a strange bunch with an agenda I will never quite fathom, but Is my Mini experience typical?

[Blue62]

Have found a Cooper that fits the bill, on a 15 plate with 12k on the clock, which I'm a little sceptical about. I've only had a quick shuffle round so far but the pedals are pristine while the interior door pulls are filthy which has got me thinking. Any tips on what to look at on my next visit and any way I can get a better idea of whether it's been clocked?