I've just removed a faulty fuel pump from an Audi A8 4.2 V8 to find that Audi want nigh on £600 for a new pump and assembly

I've removed the pump from the assembly and its marked as a VDO pump, there are no other part numbers on it anywhere though

Does anyone know where I could maybe get a replacement for this rather than having to pay for a complete assembly from Audi.

Thanks