Finally got it up and running today, well on 2 cylinders only, can't seem to get any fuel through number 1 and number 4 injectors. Checked injectors and pipes these are ok, tried holding open flap in metering unit that didn't make any difference. Is there any other tests or things I can try or is the metering unit knackered????

 

I'd try un-doing the injector pipes for 1 & 4 and very quickly seeing if fuel comes out when cranking (briefly mind), also take the injector lines off and see if they are clear (blow through them) and lasty swap 1 & 4's injectors with 2 & 3

 

I've done that, even had it cranking over with no injector connected just the injector pipe in the air, still no fuel

 

Well that either means the pipes are blocked (or possibly bent as they have metal sections), or the metering head is fucked, my money is on the metering head (fantastic inventions )

Have you had all 4 pipes off at the same time to 100% say 2 & 3 are injecting while 1 & 4 aren't?