I have come in a few years late on this thread, but I got my PPL with Air Touring back in the late '60s. In those days it was known as the Air Touring Club (the 'Rallye' prefix came later) and operated out of an old control tower (almost certainly now demolished). The club had (I think) 3 Rallye Clubs at that time. As these were not cleared for spinning, that part of the training was done in either a Tiger Moth or a Chipmunk belonging to another club (Kent and Sussex Flying Club?). I still have a picture of myself looking like a Biggles character in the Tiger).
At that time there must have been at least 6 flying clubs at the airfield. I remember Colin and Margaret Dyne well. Margaret checked me out before letting me go for my first solo and Colin tore me off a strip one day for being very late back with a plane and keeping others waiting (I had flown some friends up to Silverstone to watch the motor racing and we were held there before being allowed to take off for the return trip).
My main instructor was a chap called Martin Jeffries who later left to take his Commercial License. While I was there the club moved into a brand new hangar on the other side of the airfield and the whole organisation became (perhaps sadly) more organised and professional.
I haven't been back to Biggin Hill for many years and I expect would hardly recognise it today, now that business aviation seems to have squeezed out most (and probably all) of the clubs and, from what I hear, is not too friendly at all to mere recreational fliers. But I still have happy memories of sunny days (the sun always shone in those days!) sitting on the grass outside the old clubhouse waiting for my plane to land so I could go flying.
As a postscript, those were the days when Biggin was the home of a still-airworthy Lancaster together with a Spitfire and a Mustang.