I think John Grzybowski moved to 248 course at Church Fenton. Memory's a bit hazy, but possibly caused by a broken limb? His father was SATCO at CF.
Two other names that I recognise, and sadly both killed in flying accidents:-
John Fox. Jet Provost Gouthwaite reservoir 1978.
John Garnons Williams (no hyphen). Squirrel helicopter Tern Hill 2007.