[Arran]

On the schematic it looks like one side of both filed coils, #60 and #62 are tied together and connected to the blue and white wire. The other end of one filed coil #60 is connected to the center tap of the output transformer primary #58, both are connected to the green and white wire, which is connected to B+, which is also connected to the output side of the filter choke #67 and the screen grids of the power output tubes. The other end of the other field coil, #62, is connected to the blue wire, which looks like it is connected to chassis ground. The green wire and the white wire are connected from the outside legs of the output transformer primary to each plate of the power output tubes.
If you can't find a decent tie point for the blue and white and the blue leads I would add a terminal strip on one of the speaker baskets with some nuts and screws, just to make it secure, or use one of the output transformer bolts. Although it does look like the larger speaker has a terminal riveted to the basket, that would work for the blue wire. I speak about the colour code that Philco used originally, but I noticed that the Hammond transformer also has a blue wire lead along with a brown and a red one, you don't want to get those mixed up with the originals of course!!
Regards
Arran