Not sure if I like being called a Boffin ? (apparently a nice way of saying a Geek, Nerd, egghead or spod)
Regardless you have an Eagle Farm made machine which is a Rover 45. The engine isn't the original unit so the machine can't be dated very accurately, but in saying that I'd say it was probably a mid to late 1980's machine.
It's mechanicals look pretty good but the chains require adjustment and also are in bad need of lubrication as they are very dry.
Is that a good enough info from a Boffin ?