This is a fairly simple single cylinder engine. An interesting aspect is the smoke effect painting on the base. I'm not sure if this is original.
The horizontal boiler is 39mm diameter x 97mm long. It has a blued finish, which I assume is original (unless it's been boiled dry at some time!). It has a whistle, safety valve and steam connection. There is no water level indication. It is mounted on a typical JF firebox over a meths burner. Attached to the firebox is a dummy brick effect chimney.
Steam is fed directly to the steam chest with no control, superheat or lubrication. The cylinder is double acting with a piston valve and slip eccentric reversing. The cylinder is 8mm bore x 18mm stroke. The crankshaft has a 57mm diameter flywheel, the rim of which has a groove for a belt drive. There is also a small pulley, 11mm diameter, on the end of the crankshaft. The cylinder mounting and crankshaft bearing trunnions appear to be cast alloy. The base is pressed steel with paintwork that appears to be original and in good condition. It has an interesting smoke effect on the base, which I assume is original.