right, had another look today.

took the sender out again, and took the tube off to see if the float was a magnet, a bit like some senders we use at work, where you can just turn the float round and it will read properly.

anyway, its not like that, there are 2 thin wires that the float passes over with a wiper. so put it back how it was.

tried the custom callibration again, and low and behold, it fooking worked!

what joy, so i put the dash back together and re ran the sender wire throught the conduit...

turned it on again and the cunt was just sat on empty!

so i disconnected the st700sr, boost gauge and the fog light switch as these were all disconnected when it did work, and the fuker was just sat on empty still.

CUNT!

if i put the sender wire to earth, the guage reads full, so what the fuck is going on?!?

also i found that the main seal that seals the black plate on the fuel tank is fucked, hence why the god damn tank leaks! so need a new one of those too!