[Arran]

The wiring is a real mixed bag. Some cloth, some flexible rubber wire and some rock hard rubber. Luckily only the transformer wire was actually falling off. I'm inclined to leave the rest alone.

Yes, that is the output transformer and it's good

I find the tube lineup a bit odd. 84, 6A8, 78, 37, 75 41.
I wouldn't expect a set from '39 to be using 75s & 78s

I've seen a more bizarre tube combination the that, a friend in Alberta had a 1939 or 40 Philco bakelite that was not only an AC set but used 2.5 volt tubes like a 2A5 and a 58. Maybe they got a deal on the older types and thought they would build a set around them. Some of the later models with a similar chassis to yours used a combination of octals, loctals and old style tubes like 41s or 84s. I need to have a look at that chassis again, Ron was asking if they used more cloth wire in the 1939-42 Canadian Philcos and I think they did.
Regards
Arran