Cheers for the response. The gasket was a guess as everything else seemed to be working normally. Turned out to be a lucky guess at that! She is now at least running if not very well, early days. I made myself a coffee and sat down to trace all the wiring and I think I have it all identified. Someone told me not to judge 1980's wiring logic by 2020's standards which seems to hold true. Everything seems to be working but for the indicators so we seem to be stumbling in the right direction. Mainly just cleaning up the rust and oxidization now.