If it was immobiliser related it wouldn't crank so don't think its that.
I'll have a look see if the injector plugs are round the wrong way, if it was something mechanical top end, surely it wouldn't run on easi-start? It'd just clatter and make an awful racket?
As for the fuel pressure when cranking, tbh I'm unsure but 100br+ sounds relistic and 120br is when it tries to fire and then pressure drops below 100br and then there's no hope.
Thanks for all the suggestions I'll have a look tomorrow and maybe try swapping some random sensers, cam and crank, although if that was the issue would expect to see a correlation fault code. Before I start stripping it down looking for something mechanical...