There were lots of connectors in the 50s and 40s similar to this, all using randomly positioned pins. Different manufacturers used different plugs for their sets. All I can say about it sorry if that's no use. Could be military related though looking at the cloth cable and general bulkiness of the connector body itself?
Thanks Cath and Brian, I have some schematics for the T18 that show a rectangular 6 pin connector used in various places. I haven't found any photos as such. My one has a seventh pin the same form as the other six but I suspect it's just there for registration as it doesn't appear connected and I'm unable to open up the plugs. I tried web searching for Carr but the nearest I got was Carr-Lane although nothing similar.
Looking closer at the Baird connector the 6 pin grouping is similar but it appears to use a group of 4 smaller diameter pins in a square along with 2 larger diameter pins. The right era and very similar but not the same. Good suggestion though.