Ah Pete, you know you can't resist a good looking bike.
Its probably cause its got a nice round fuel tank like an early Husky!
I believe its a '62 m3 200cc Sherpa S(crambler) as Dave says.
I've got a '68 125, and I'm building another one to race with a 250 Mk3 Pursang engine. These models looked very similar to the one you've posted, but run a thin fibreglass tank and a down pipe.