[Arran]

 I think I know what you meant about the speaker connector, there was a three pin type used in some Canadian RCA and G.E models in the early 40s, but I don't think any of my sets use them, the pin spacing is the same as a three pin "B" battery plug, I believe that they were made by Ebby. I think I may have some someplace. With regard to the volume control, sometimes you can swap shafts and wiper between controls, if they are both controls of the same make, that "C" clip can be pried out and pressed back on.
Regards
Arran