Hello again,
The yesterday’s message should have read:-
“Don’t recognise this one – it’s nothing like a Sociable engine , where the flywheel was central, and enclosed in the large unit construction crankcases/gearbox casting, whilst the two cylinders were separate castings.”
I passed a copy of the photo to John Underhill at yesterday’s SOC AGM; he will do a bit of research, as neither the picture nor the engine number rang any bells.