I have now got to the bottom of the problem and will share this with you incase it helps.

So the original problem was that the pump was on constantly. The previous owner had obviously had an issue and wired it directly.

The ignition positive to the relay had been diverted directly to the fuel pump and the ground to the relay had been cut and tied off for some reason.

Firstly I wired the relay back to how it should be or so I though which made it work but it was buzzing. Turns out that the ground wasn't wired back up correctly so check the wiring if this is the problem.

Once this was done it was quiet and primed but did not re-engage the pump when cranking so it would just stall, i suspect this was the original problem and the reason the former owner had directly wired.

I took an educated guess and changed the speed sensing module, it was a pain to get at but has sorted the problem out.

it is now working properly.