Thanks for all the advice and tips.
I can't see this being a long-term investment; at some point my savings are going to have to go on a deposit for a house. I was looking at it more as an alternative to earning about 20 p a year interest in the building society. However, I don't want to let down any other group members either.
Rental prices down sarf are fairly OTT. I can hire a bit cheaper through the RAF, but it's a trek to my nearest stations with flying clubs. My thinking was that, if I bought into a group, I would get some regular flying done for 6-12 months ... something I'm desperately short of at the moment.
No hurry to make any decisions though. There's Christmas/New Year/job hunting all to be done.