Sorry about the mix up with Mike Harrod. I could swear that the you tube video had 1965 imprinted on it.
Anyway, Walridge has this posted it its' HELP AND ADVICE section.
Norton/Matchless G/N15 Hybrids
Almost daily we get asked for an illustrated parts book and workshop manual for these bikes. I have never seen one but if I ever find the time I’ll try to do one. I remember asking Gus Kuhn motors in the late 60′s for one for my AJS “33″ and they gave me a mid 60′s AJS Instruction book (as supplied with the bikes) and a Norton Atlas factory workshop manual.
The 1964/5 parts book has limited pictures, ie motor, transmission and forks. 1966-8 has no pictures so you need time and an imagination because parts are not always listed in the most logical places. For 1968-70 a few pictures crept into the early Commando parts book and then from 1971 onwards they did a beautiful job.
"If anyone has specific questions about what goes where on these bikes I try to help them, time permitting."
I've seen them with their van at a couple of swapmeets with N15s and others in it.
So with what he has said in the last line,Maybe give the sight a look http://www.walridge.com/
and give them a call