It may be that I've come across a small number of these generators in store. Based upon the Coventry Climax "Hillman Imp" unit, they were used as generators for the Blue Streak missile system. Now, they are not everybody's cup of tea, but before I go and dicker for one, perhaps there are others who may be interested? There may be economies of scale!
I've put up three representative pics of John Rogers' unit at
Regards,
Kim Siddorn,