Well, that is a curious engine and no, I don't have it in my NNIB (Numbers Not In Bacon) list. Its an entirely new one to me. Nothing like a little mystery is there.
I think the blower cooling is a later fitting as is the crankshaft extension. I think that is a blower set up from a Villiers industrial engine grafted on to a normal motorcycle engine. The usual motor scooter/microcar blower cooling completely encloses the engine not just one side plus Villiers fitted a special cylinder head with transverse fins because the cooling air was coming from the side. This one has a standard fore and aft head. Spark plug access would also appear to be a bit odd.
The crankshaft extension also looks half done. I can't see Villiers doing that without at least providing extra support and an oil seal.
Don't get me wrong. The bloke who did this knew what he wanted, used all Villiers parts to get it and did it quite well but I don't see it as Villiers factory issue.
Isn't it nice to have one to scratch the head over.
Cheers,