Just came across this site.
I got into speedway in the 70s when it was hosted at Eastville, Bristol and Gresham was one of the Bulldogs.
Gresham was a revelation; he was average for the first year I watched, averaged 7-ish. The following year he was up there with the best, I don't know what happened to him between seasons.
And I was at Eastville when Gordon Kennett was a guest rider for another outfit and the two clashed; Kennett was quickest away from the gate but Gresham was all over him like a bad rash.....Kennett went down under a challenge, threw his arms up in the direction of the referee and the referee obviously bought it, red-lighted the race and disqualified Gresham.
The two of them had some fisticuffs on the track immediately afterwards.
I admired Kennett up until that point, afterwards not at all; he was outridden by Gresham and chose to bite the dirt and bellyache.