Brian Jones.
I knew he went to a fairly posh school (turns out it was Cheltenham Grammar School for Boys), so I wondered whether maybe Christopher Robin had gone there (he hadn't). But it throws up an interesting link between Jones and Alvin Stardust, in that the Head of the school (now merged) is Shaun Fenton, son of Shane (apparently. This is from Wikipedia, after all, and its not beyond pupils to have a prank.)
But i do remember, from when I lived near the Hundred Aker Wood. Didn't Brian Jones buy Milne's old house in Hartfield?