We spent last week on holiday in Yorkshire and visited the steam railway station in Embsay near Skipton. There is a generator set there, skid mounted with a Ricardo engine as driver. The condition is tatty but everything seems to be there. I doubt that the preservation society have an urgent need for such a machine and may consider selling. I didn't enquire as there wasn't anyone around and it's a bit big for my taste (and for the boot of the car). I may remember more details if anyone is interested. Sorry I didn't take notes at the time, will try better next time, honest guv. I would guess the date at about 1950's but, as I say, it's not really my interest.
John