I notice that one of the "connections" to each bus-bar appears to have thicker wire (the ones to the centre of the bus-bar). Is it possible that these are two-wire connections to something like a thermocouple?
Not really. Go back to SoS' original photo and look at those busbar connections. The thicker section is a piece of sleeving. You can see the end of it under the zip tie and the single wire coming out.
Zip ties. Not used much in my day. We preferred cable lacing:
Cable lacing - Wikipedia, the free encyclopedia
Some of those wires appear to be pulled pretty tight as well.