Welcome to the asylum, livingdeadhead. Perfect screen name for Halloween. Nice looking R65. Appears to have been well cared for.
Did you buy the bike from a local dealer? That would be the place to start. It's my understanding that, in England, a bike's registration remains with it when it is sold. That would make it fairly easy to track ownership history for English registered machines.
Unfortunately, it doesn't work that way here in the Colonies. I have three Airheads and only know the name of the last owner because I knew them personally.
I can tell you a couple things about your bike's history... those are not the original carburetors. 1980 models had flat top Bings. You also have up-graded ignition wires and plug caps. Check your ignition coil/s as you may have newer items under the tank.
Whoa! You've got some history already. Cool. See, the plan is working already.