Oh I don't care about the stripped threads lol, that's easily solved by hammering the bolt in. 
Amazingly it seems to have worked, diff casing came off and allowed me to to get the bearing square so the speedo drive now fits square and it holds a litre of gear oil. Of course the reused diff seals are leaking as expected so can't put any more oil in than that.
Also just checked fuse Dee mentioned for heater controls, both fine.

Amazingly it seems to have worked, diff casing came off and allowed me to to get the bearing square so the speedo drive now fits square and it holds a litre of gear oil. Of course the reused diff seals are leaking as expected so can't put any more oil in than that.

Also just checked fuse Dee mentioned for heater controls, both fine.