[QUOTE=geoffs;271910] Most senders are only a pot, + on one end, - on the other and sig out the middle. Swap the + and - and the signal will be reversed.
Have a look and maybe try that.
Just tried swapping the wires on the trim sender, and the gauge still reads wrong way round
I am going to try and alter the sender unit mounting position, it means drilling a couple more holes but I don't know what else to try.