Thanks Nick for the photos, they match my unit precisely, right down to the brass gaskets. Also solves the mystery of the the S/50 brass plate. The same plate was glued onto the valve chest of my engine, of course I had no idea that it had any direct association with the governor. Is a bit worse for wear and so I did not put it back, I prefer to leave it off for now, but will be sure to always keep it with the engine.
Paula, thanks for the tip on the lubricator, that is the way I received it, have not run it on steam yet but will take your advice if I do!