Sandown isn't too hard to spot, but it's not in the best condition, only 600m usable and completely unlicenced.
How about Exeter - Kemble?
Would be more accommodating than either Bristol or Cardiff. Kemble has a great restaurant, nice pool table, remote control car racing track, and some great views of old aircraft being taken apart. Also worth popping in to chat to the Ultimate High team about more advanced training once you get your licence.