another Quarterbridge slide, undated. 
The bike number appears to be '82' and with that distinctive helmet wondering if anyone can identify the make and rider and possibly year/heat??
regards

Just a guess.
It's Junior 350 practice. Maybe Abe Alexander. Drum brake suggests it's taken before 1975, and after 1972.
Discuss.

Well the slide itself has 'Jun 71' impressed on the border of the slide, so assume it would be from that date

According to the program and results list for 1971 number 82 in the Junior was Chris Gregory on a 348 Norton. He "failed to complete one lap ".

I am sure George Ridgeon used a helmet similar to that.

That's not George - I know him and as far as I know he only ever rode in the Manx on a 350 Greeves Oulton (which I believe he still has). Doug Lunn used to use a metallic painted Union Jack lid but if it's 1971 it would be too early for him.

Definitely Chris Gregory-1971 Junior

Looks like Bernard Murray to me but I might be wrong,?