I had the same issue on my TVR V8S and did all of the things that you have done. In the end I traced the wiring from the pump and found that someone had fitted an immobiliser rocker switch in the circuit, in my case in the boot, that I must have caught whilst in the boot. Flicked the switch and the car started straight away. Someone more knowledgable than me will probably have a more likely solution. There could be a break in the wire from the pump.
