One other thing, fuel seems to drain away quickly from the pump after cranking, is this relevant?

Yes.

If the HP pump has no fuel to suck it cannot get any fuel to pump.
They will not suck air.

This may be problems priming the new system or may be the initial problem got worse.

Pump the primer bulb, it should get hard.
Assuming it does....
Get a helper and some easy start...open an intake pipe after the air filter.
You pump the primer so it is hard, keep pumping, get helper to start cranking...you pump the primer bulb and squib easy start into the air intake pipe.
It should try to fire on the easy start, keep pumping and squibbing until it runs on its own.

If this doesn't work, come back and we can explore why it wont start.

 

Thanks Dancingdad,
I’ve tried that already: made sure all air was purged out of the system using the air bleed and primer bulb. Had fuel coming out of the temperature sensor LP bleed and reconnected fitting. Bulb was hard. Cranked and got her running on easy start for short while but never saw fuel pressure come up in the rail and no sign of engine firing in the normal way? The pressure sender is ok I believe as at one point had that off and put compressed air on it and verified good reading on live data stream. The wording of the faults is vexing me: seem to suggest a ‘circuit’ , wiring fault?

 

Juts for interest sake .................... Where did you get a compressor able to push 350Bar?

 

Haha machine mart! 60psi just enough to see it register something on the analog

 

A compressor for doing dive bottles would probably do it.

 

So the faults were related to dodgy contacts in the connectors at the pump. Still struggling with inadequate fuel pressures however….

 

Huh? ..................... what faults? ................... what inadequate fuel pressure?

 

So I have resolved the fuel pressure regulator circuit error (connector at pump replaced) and now I’m getting not much more than 100bar on cranking and no sign of combustion. Leak off pipes not showing any flow at all. Is that because nothing is passing into the injectors due to the low pressure? Can it be anything other than the pump itself? I’m convinced there is fuel supply to the pump?