Thanks guys - interesting reading. Fortunately, I have most the components other than cylinders and a magneto. I bought a job lot incredibly cheap which had most of the internals, including a crank, and the outer cases.
Whilst it probably isn't the most efficient way of doing things, it makes it quite fun to slowly build things up into a full bike.
I'm also looking for:
Centrestand
Footpegs
Brake pedal
Rear mudguard
Toolbox
Petrol tank
Cylinders
A nice chap in Aus has parts available which I will use if necessary, however if any are available closer to home it would be preferable.
Kind regards
Tom