Hi Leon
I didn't take much notice of the front tubes, but you're right, they are half round. And I was wrong about the forks too, they are the earlier type. Hmm, very interesting. Now I see that the oil pump arrangement is not the type standard on later 4hp models either; but still the 3 1/2hp doesn't carry oil in the tank. I wonder if it is cobbled together with whatever was to hand at the time? The sidecar frame does however look standard Douglas of the war time era
Cheers, Graeme