This perennial favourite was in production, in many variations, right from the early days of the Mamod brand in 1939 up to 1979 when the entire Mamod range was modernised. In those 40 years, around 1/4 million were made. I'm sure everybody reading this owns one or owned one as a child!
This particular variant was around mid-70's vintage, with the vapourising burner and water level plug. It has been fully restored from rust-heap condition and the colours are not quite correct, although the general scheme has been preserved.
It is an overtype engine with everything mounted on top of the 1 1/2" diam x 3 1/2" boiler, including the 5/16 " bore x 5/8" stroke cylinder, standard 1/4" safety valve, 1 1/2" diam spoked flywheel and the purely decorative chimney, which doesn't even cary the exhaust steam. As acquired, the steam was nominally superheated by passing the feed pipe under the boiler through the flame. However, this was a subsequent modification by a previous owner. I have since removed this mod and also corrected the orientation of the boiler.