I've previously mentioned that this bike looks great Fraser. What a great find!
I'd make the suggestion of keeping it stock. I'm not sure how much money you're willing to put into restoring it further before making a sale but if you want anywhere near a decent asking price ... you're going to have to repair OR replace the front upper cowl. The tank has a few small dings, some small marks over the bodywork (from what I can make out).
The all important bits would be maintenance and ensuring the bike is running. Changing the oil, take a look at the chain/sprockets, and a quick peak at the calipers (front & rear).
Ahhh... you already know what the bike needs Fraser. ...
I hope it turns out just the way you want it to. Enjoy it - and have fun with it!
Shindy makes a decent damper and they also sell the fork bracket. Dampers vary in stroke, just as the fork brackets vary in diameter. Attaching the other end of the damper, to the frame - can be done by use of a bracket or by fastening directly to the frame.