Hello Dave it is a nice bike as far as I can see on the pics.
You indeed have to work out if it is a G.
The special items of a G are the gearbox(must be QDH letters stamped in the burman shell) in close ratio trim which is difficult to see on the outside although I can see that you have a smaller chrome cover behind the kickstarter which I think is not a QDH.
The gearbox sprocket has to be 21 teeth for topspeed 85 mph, I donīt think I will ever have the nerves to do that but next year I would like to try it out on the spa/francochampscircuit during the centennial.
And the magneto should be a lucas racing one, the KR 1 ( they are almost impossible to find,I know one for sale but it costs 1200 euro, 800 pounds, so you can imagine that I am lucky that I have one.
The magnetochaincover is genuine with SPECIAL on it.
The engine was a no 10 and had G stamped on the side under the cylinderbase and on the other side a no starting with K.
The frame no should start with K as well but they did not match in that time with the engine
I have a list of engineno that should be a G special, got it from the arielclub england.
the metal toolbox looks from a later date, mine, I made myself from a picture, has a leather cover.
The rest of the bike is similar to the F.
It looks in good condition so what you maybe first must do before you start to restore is ride it.
Keep me informed and from Holland a merry christmas and a happy 2008
regards Chris