Hi Chaps, need help!!

Vehicle was recovered into us by the RAC, they had already fitted a new fuel filter but fault still existed, the owner intermittently breaks down. So whilst in the workshop you leave the engine ticking over, usually between 10mins and 2 hrs! the engine just cuts out without warning as if someone had just turned the ignition off. Fault code P2292 fuel pressure control malfunction usually pops up. However, other various U codes sometimes appear, predominantly U0121 CAN coms with ABS, and also ‘sometimes’ a parking brake and stability control message appears on the dash readout.
Tested low fuel pressure low around 0.6 bar, high 230 bar, seem OK? checked injector leak off, unsure whether being led up the wrong garden path with the fuel pressure fault code or is it some kind of CAN communication problem?
Appreciate your thoughts in advance, Stuart