I would use a ramp to take a look underneath in order to check for rust on the engine sub-frame and associated metal work. I've owned a Cooper from new(55 plate) and was horrified at the amount of rust on a 22,000mile, 5 year old car. BMW quality, I don't think so.

The metal sub-frame and quite a few other metal bits under the car are only painted and although the metal is thick, I would think that the corrosion would have lead to a MOT failure in a couple of years(by then a 7 year old car) .

By the way the car lives in a car port and is seldom used in the winter(convertible).

I've now treated the rusty bits with Dinitrol and I'm sure it'll be good for a few more years. The rest of the car has been fine.

I contrast I've looked under my step daughter's A3 which is 60,000 miles 7 year''s old and it looks perfect., probably because the underside is protected by a plastic tray.

Just had exactly the same situation buying a 2006 56 Mini Cooper from an independent dealer.

Background:

http://www.honestjohn.co.uk/forum/post/index.htm?t=85171

The dealer had no service book with the car. In fact, the car had no owner documentation at all (apart from the V5 - the car was HPI clear) and just the single remote key. However, he did have a printout of the service history from BMWs service system. As part of the deal to buy the car we insisted that he get us a Mini service book, stamped by the relevant Mini dealers. To give him credit he did just that with no additional cost on the originally agreed purchase price. The book was back with the dealer when we picked up the car and paid the balance.

Since buying the car we've picked up the relevant Mini folder, owner's and audio handbooks for the car from EBay for £16. Scarily there were blank Mini Service Books for sale on EBay too.

We've also been in touch with the local Mini dealer with regard to getting a new key cut. On querying the registration number on the Mini/BMW system they confirmed that there is a TLC package still valid on the car until October 2011 - Result!