eddy dar wrote: have also managed to communicate with the cu and got fault code p0215 stop solenoid. Cleared it and still wont start.
Clearing codes won't fix the fault if the fault is permanent and being reported correctly. P0215 is an indication of a physical condition and not the problem it self.
P0125 - stop solenoid, is telling you the car is inhibited from starting. I would guess the 'stop solenoid' is controlled and referring to the 'double pole relay' in the BSM module. The thing you have to do is find out
WHY the double pole relay is not energised, this will then allow you to sort that and all the other things will fall into place.
eddy dar wrote:As I have changed an injector the whole system needs checking for air leaks/fuel leaks.
After the P0125 is cured
What does starter speed and fuel pressure in the common rail show in 'live data' when you try to start or even running on gas?
or anything else that can inhibit the fuel supply from ECU control?
A bit like this?

- Citroen C3 Delphi 16v idle live data (part)
and probably the immobiliser

- electrical ECU locking engine Immobiliser C3