you will more than likley find that some under knoledged idiot has pulled a 12v supply directly to the pump, have a check under the rear seat, thats normally a popular place that I have seen attacked, otherwise, the fuel pumps supply wire is a black wire with a red trace that runs along the sill towards the back of the car and goes through the floorpan under the rear seat via a rubber grommet. unscrew the plastic interior trim that runs along the sill and have a check for signs of halfords style of repairs/wiring, when you find it, I suggest ou solder it back together and heat shrink it/ or what ever the damage is and obtain the correct fuel pump realy. there really is no reason for shit wiring! drives me nuts!!

hope you can solve your problem!