again, a fitting i've never seen before or since

Ive never seen one of these in my life either unfortunately however when Eliot (supersix) comes online he might be able to help you out or colin!

I'm sure would work first time if powerd up, fittings of this era never seem to suffer with the damp and dirt

Oh i totally agree this could probably be immersed in water at the bottom of a tank snd still work lol.

I have seen one of these before was in the old council offices in Truro was mint condition but missing cover plate