I'd agree with the gliding suggestion above. It's an excellent way to discover flying, and the skills you learn will help a lot when you come to fly aeroplanes.
If you go to a gliding club where there are also powered aircraft, you might get a lot of interesting flying - even if it will be as a passenger. If you're in the Midlands, Husbands Bosworth and Bidford are two good gliding clubs where you will also find interesting aeroplanes.
Bidford's often a bit muddy, so there's lots of aeroplane washing to do.
In exchange, there are Cubs, Jodels, Chipmunks, Tiger Moths and all sorts of other fun machines to have goes in.
