I run a seperate live supply to pump anyway (though I also run aftermarket loom)

I would suggest its your immobilser at fault or fuse box, check the lives etc at pump relay in box then you will know what is going on, also not read it all fully but the plug behind the bumper is ok isnt it? check lives and earths there

also check cut off switch in n/s kickwell, could be at fault killing your pump live as this is AFTER the relay in fusebox.