Looking to buy but don't know much about cars

Hi all,

I'm in the process of selling my Lotus Elise to buy a real car (and something with a boot, although still no air con). Yup - my trip to the Silverstone Classic Race Weekend and a walk around the Cobra Replica Club enclosure told me I had to get one....

Question is I have very little knowledge of car mechanics (the Lotus is not a car you can easily maintain yourself) and I don't think you can get a Haynes manual for a Cobra....

I've subscribed to Cobra magazine to start learning a little but I need to be on a steep learning curve to buy one with confidence before the summer(?) is out.

I think my budget will reach to £15k and looking on Autotrader.co.uk there appear to be a number under this price, but am I being realistic to buy a (reasonable) car for this amount?

The key questions:

a) What are the key things to look out for when buying? (ie. must have SVA, anything under 3.5l a no-go?, etc)
b) Where can I get a professional opinion on one before I buy (ie would an RAC check be sufficient?)
c) Am I being realistic with my budget constraints?
d) Is this really a car to get if the extent of your car knowledge is just about knowing where the front and back of the car is?

Any advice gratefully received.
Gops