Don't think its Michell's engine. She has a double drum, although only one would be visible from side view, and a flywheel and sweep rod as it was a winder. Picture looks more like a pumping engine arrangement. Michell's also had a wooden shed roof type structure over the drum and flywheel to stop brake slipping if it was raining, as sometimes happens in Cornwall! Also I think houses in background are different to ones behind Michell's.