I have the same problem... since I changed the fuel pump - as DerekT said I was probably sold a 110 unit by mistake.
I keep and eye on my fuel consumption, and zero my odometer at every fill, so I know that by 360miles I have about 10 litres in the tank...
One day I will get around to removing the pump and bending the wire that holds the fuel gauge float - or should I say callibrate the sensor!