fantaman I used to go gliding at Weston on the Green more years ago than I care to remember. Not sure whether it is still there. It was known as the Oxford Gliding Club. Got my Silver C Ht there in an Olympia. The place being an RAF Station was also used as a dropping zone for Parachutists from a tethered ballon and aircraft from Benson and Abingdon I seem to remember during the weekdays.
Just seen Sedbergh beat me to it. Shenington ( Edgehill ) I had a two week camp there as well years ago when I was in the Coventry Gliding Club. Good for ridge soaring when wind in the right direction.