Lowglider, why did you choose that name? is it fate calling?
For acquiring the basics, if you are starting from zero....why not book a week's course in May at my gliding club? (you can google Shenington gliding for terms and conditions). And then, having a sound grip of the basics, go on to the motor glider rating, which is an economical way to fly if you insist on an engine. As for London to Banbury, good trains, etc, and then a taxi? and primitive accomodation is available on the airfield, or you can stay in a very nice B&B....or at the local pub.
We do welcome Londoners! quite a few, actually.