If I remember rightly the A,B,C etc we're the form year grades, ie A's the clever un's B's C's etc lower down, but then there were the House groups such as Firle for sports activities etc that crossed the year divides
Ah yes, here's a few others I recall;
Ma Bramwell
Jack Widdup
Sedon ( alias Sammy chisel)
Roy dyer
gram Wilcox
Pete Hollands
Bill Shields ( the fly catcher)
Cyril Bear? Music teacher