Spitalgate housed not just a gliding school but was a gliding centre too.
Memory is a bit dim now so somebody correct me if I'm wrong, but I recall there was originally No 1 Gliding Centre at Swanton Morely, then No 2 GC was formed at Kirton - in - Lindsey, then the two merged and became Central Gliding School at Spitalgate until the Army made this airfield unuseable (as they are wont to do - just look at Catterick!) CGS then moved to its present home at Syerston.
GC or CGS, they had a gliding school operating in parallel, but I don't know the numbers - they may have been in the 63X or 64X range.
I never met Pete Bullivant, but as far as I'm aware, he was an instructor at the centre/CGS not on the school.