No clues so far regarding make of engine, magneto or carburettor. I have now found what I assume is an engine number on the crankcase.
Thinking about what to do with this machine I may clean up one side and leave the other as found. Amazingly the large nut holding the wheel on came undone with no effort, one was almost finger loose.
Photos show engine number, axle with wheel removed and oil level sight glass on front of crankcase.