Right another update - not a good one.
So spent the day on the disco again today, to start with i re-tried the gravity fed line and had alot of stalling issues this time round, no air at all in the system. So it may of just been a fluke that it previously ran nicely!
So i spat my dummy out and removed ALL injectors, soaked and cleaned them (they where pretty dirty but cleaned up fairly well), removed pipework that goes from pump to injecters soaked and blew out with airline (all cleared and clean so no issues there)
Put it all back together, bled the system still using the gravity feed, fired up, ran lumpy for 10-15 seconds, cleared up ran quite nicely, little to no smoke, ran itself at about 4-500rpm (i know its not ideal but better than it has been) for a good 3/4minutes then died and then doing the same as before.
I have ordered a new lift pump and a "boost pin" as these are cheap parts to replace. Before i go to the route of new injectors.
So i guess my question is, am i doing the right thing here? Am i missing something? Im really hoping the pump isnt knackered due to the price of them.