Thanks all for comments.
Another question!
Which engine is this?
The engine had the number 10003 chalked on the roll, according to the TER that is an M-Type compound convertible. However, if you look closely at the forks it has PW 623, which is again an M-Type convertible 10341.
I though it was an interesting engine, the shape of the valve covers is unusual, looks like a very early piston valve design, so 10003 would make more sense.
Any thoughts?
David.