I have worked out what was going wrong. When the short happened, everything got hot and the plastic around the green connector melted, and something then pulled the connector out of position. Now cold, i can see the connector is about 5mm out of...

Bit of a c***up. I haven't finished rebuilding the lower dash so have been driving around with lots of wires hanging loose, which was a daft thing to do. On the last drive, I got a load of smoke in the cab. I stopped and sorted it out temporarily...