Well I finally had enough of the fuel gauge giving silly readings (mainly low fuel).
I decided to attack the sender unit and see if there was a way to sort it, and there was....
Locate the plate covering the sender and remove the three 10mm bolts.
Unplug the connector to the sender.
There are a series of nuts and bolts securing the main cover plate, take them off, they are 16mm, a few allen bolts (sorry forgot the size) and when the seats are pushed out of they're securings there are two 13mm nuts to take off....the plate can come off now.
Now you can take the pipes off, they have two protruding bits you squeeze together and the pipe just pulls off.
Using a screw driver or drift tap anti clockwise with you hand and the ring will turn, eventually you can do it by hand.
Carefully lift out the sender assembly. Carefull not to spill it..drain back into the tank whats in the reservoir, this makes life a little bit easier and cleaner.
There are two push clips securing the float assembly in place, just press them with your fingers and unslot it....it will still be connected on the wires so take a little care not to be too rough with it.
Now the tracks which the arm moves for the pick-up are probably worn as you can see....
The tracks on mine were worn right on the quarter full mark. Contact was little if at all. I gently re-bent the copper spring contacts so that when I moved the arm you could just about audiibly hear and slightly feel the contact crossing the track...
As in every good haynes, re-assembly is reverse of destruction!!
When you place the sender back in the tank there will be a little resistance as it wants to float, just push it down and secure the plastic ring in place.
I tested mine before fitting the plate and seats back in.
Engine started fine with no leaks........and........fuel gauge went straight to just over half, it was on about an eighth of a tank before I did this...
Hope this helps.