I have one in .177 not fun to work on but a decent rifle. you should join the UK AirgunBBS and do a search there they seem to hold the 45 in high regard
This gun has the cross bolt above the trigger so I’m guessing mid 70’s. the reviews I’ve read are mixed on the model 45, so I’m hoping for some reviews from members who have experience with this rifle.
I have a late 1980s model 45. with several thousand rounds through it and no troubles other than it eats scopes for breakfast five or six of them so far. Had my Bushnell Trophy on it for a time but took it off for fear of destroying it. Recently put some cheap lightweight Winchester branded scope on it and it seems to be holding up better than most. It's a shooter though very accurate one inch groups at and past 50 yards. I was told when I purchased mine that it was one of the early units with the synthetic seals and the guns before had leather.