I think it was him. Apparently he was shouting "me brains gone to Mars" as he invaded the pitch. Against Chesterfield at the Lane in the corner between John Street and Bramall Lane towards the end of the game he jumped on to the wire fence and started to climb shouting abuse at the Chesterfield fans, he reached the top and fell off with a sickening thump. I was on the terrace straight behind him.
I first went to a friendly at Saltergate late 1960's, we occupied the area behind the goal, a huge skinhead from the Chessie end invaded the pitch only for the coppers to restrain him.
After a night away match at Chesterfield I caught the train back and ended up in a carriage with all the raggy lads, I seem to recall your Uncle was wearing a Hitler mask, may have that wrong, they were all singing " wunderba Copenhagen" for some reason. A certain well known hooly Blade threw a passengers briefcase off the train