Thanks for the replies all. I'm currently reading studiously, but as there's no rush (this'll be car 3), it'll be a case of buying when the right one comes along. Seems there are some interesting cars on PCGB, but unless I ask a friend to approach people, it's a bit of a problem making contact.
Ideally I'm after a car that has been owned and run by an enthusiast, that has just got on and used the car whilst respecting it. I don't want a infrequently used garage-queen, and don't believe I should be put off by cars doing average 10-12k/yr mileage.
This car is quite interesting (
http://www.porscheclubgbforum.com/tm.asp?m=733799) , but I need to understand prices a bit more before really bothering private sellers. On paper this car would appear to tick the right boxes generally.