Well,
All fitted, everything back together.
Tried to start it up, same problem.
But this time, i think i may have found the problem.
While tightening with the allen key, i dropped it into a small gap and while i was getting it out, the injector rail was starring right back at me, all injectors were a bit dusty and dry except one which looked like it had petrol running from it. Didn't really think about it, then got the allen key out, then had a closer look at the 5th injector.
Got the keys, tried to start it up.
No luck, went back and checked the injector, definitly petrol coming out of it and it was hissing, a leak.
Could this be the solution?
Loss of pressure/loss of fuel?
Also, with this problem, will it be just the o ring or the injector itself?