Thought I should give you an update...
RE fitted scope but still the zero moved, so then removed the scope extra high thingies given to me, seemed better but chairgun and my clicks were way off. Once I went to the range the zero was still moving. .. so this week, Darren swapped the original Hawke mounts for some proper ones £55 and after checking the clicks were stable at home up to 20 yards, we went to the range today and so far... All ok!
One mornings test isn't definitive I know but, I think it's sorted!
Thank you for you comments and advice.
Shiny Blue EV2 Mk2, Falcon T50 10-50×60
John Bowkett BSA Goldstar SE RNRR, Bowkett Carbon Shroud/moderator/air stripper, Aluminium scope riser made by Shawn, Polished trugger guard snd am soon to fit cheek piece risers. Hawke Airmax 30 AMX 8-32×50