Camlobe,
As you say, winch launching of Gliders was restricted, though I suspect the 500' at Bicester might well have been a restriction of take off run length. In my day when flying at Bicester all launches were Aerotow, usually to 2000'. I suspect your CFI may well have been the late, great Andy Gough, who was well known throughout gliding circles. There was, as I remember, a legal requirement to release from the launch cable, when winch launching, at 1000', I believe this in concern for lower flying aircraft not being able to see the cable whilst passing below. There was a procedure called "Kiteing" however, where, on a nice day with a good headwind, and by prior arrangement with the winch operator, you stayed on the wire at 1000', he then allowed the cable drum to reel out slowly allowing the glider to continue to ascend, just like a kite. I only ever had one such launch, at Syerston, and released the cable at an indicated 2300'. At the time a winch launch was 70p a time. An Aerotow to 2000' would have cost around £7.50 I believe. I did have to buy the winchman a beer or two later.
Hope that helps.
Smudge
