Fuel Gauge problem

Was out in my scoob today had about a quarter of a tank left, but within about 6-7 miles warning light was on and needle right to the bottom of the gauge, didn't dare chance going much further so made it to the nearest garage to fill up, nearest garage was only a BP so put £10 worth of their super unleaded in just until I could get to a shell station, started car back up and needle didn't move on gauge and warning light still on, drove steady to the nearest shell garage and filled up with another £50 and the pump clicked off to say tank was full, anyway started car back up but gauge was still only reading just under half full, drove about another 6 miles home turned car off still reading just under half a tank, went out 10mins later started it up and reading full tan.   

Has anyone ever had this before as I now don't know weather to trust my fuel gauge or not anymore.

sounds like a bad connection or a suspect sender unit in the tank

Is this easy to check for Andy and an easy fix if faulty

depends what the fault is, but either way its not a big job, the sender unit and fuel pump both come out together

I had the same problem with my hawkeye and it was a sticking float. Andy if you remember we took pump out gave it a clean and put it back in everything was ok.