can anyone identify these electrical sockets

Thank you for all the suggestions – plenty of ideas – thanks again

Suggestions (most costly first)
1. Farnell have loads of “mil spec equivalent” connectors – you will need both halves
2. You may be able to find some on ebay if you look long enough – make sure you get both halves. There were some cheap brand new ones fromthe Far East as well as surplus.
3. Replace the back panel with a new made one and use D connectors – very low cost

Thank you for the update – just checked the costings – £60 to £90 each and that was for a standard off the shelf plug – have you a suggestion for a more reasonably priced commercial equalivant

I think they may be MIL-C-22992. They will be very costly, expecially with non-standard keyways which will probably be machined out of solid to order. (There is usually a default keyway for most people but the specials are an even smaller market.) If you are not going to fit it back into the Merlin then I would swallow your pride and hot wire it, or for a high class job, remove them and fit low cost commercial equaivalents in the same holes.

Thank you for the suggestion – I checked a few images on Google and they could be – but did not find any with the same sort of outside thread as mine – my thread is course with flat edges – but I’ll keep looking –

They look very much like standard Amphenol
panel plugs .