Should I be able to hear the fuel pump? My V8 is still not running however I have scanned it for diagnostic codes and there are none, I also took he top off the fuel pump relay (Yellow one under the bonnet closest to the front of the car)) and it operates with the starter, however as far as I can tell the pump does not run, I should add this disco is LPG converted and has had the original fuel tank repelaced with 2 LPG tanks and one small petrol tank in the rear wing under the petrol filler so I would am guessing it should be possible to hear it if it was running?

If u are close to the pump u may hear it with a standard fuel tank but in normal running, NO.

The car won't run! I have the top off the fuel pump relay, which I have checked and it closes when cranking. I can also fix it closed, in which case if I have read the circuit diagram correctly should make the fuel pump run. On my car with the small Petrol tank the fuel pump is just under the fuel filler, so very close to the wing, however there is no sign of any life at all

Ok then u must check the 12v supply to the pump which will be difficult unless your cranking, then the pump after it has built up pressure will cease in operation thanks to the ECU, BCM or so thing similar....in D2 Speak.
So then it's a matter of checking the wiring continuity of wiring from the supply to pump.

As u have a non-standard system it will be down to u to do the test, unfortunately.

Once the ignition is turned on, the fuel pump runs for 5 seconds to put pressure on the fuel rail.

It then stops until the ECU gets a signal from the flywheel sensor to tell it that the engine is running.

Peter