2009 Citroen Berlingo citroen berlingo van won’t start

Van ran really well and has been fully serviced, however it developed an intermittent fault causing the van to stall.
The stalling occurred usually at low revs, when cornering or on a roundabout. After the van stalled, if you turned off the ignition and turned the key, it would start again and run fine.
Took the van to my local garage when the van was running and after suspecting an electric fault, after a few hours no fault was detected.
I continued to use the van until it stalled and would not restart. At this point it was recovered to another garage, who discovered metal fillings in the fuel filter.
They flushed the fuel lines and fit a new fuel filter. Checked the cam sensor and replaced the fuel pressure sensor. The van still would not run, so they suspected the high pressure fuel pump, so tried pumping fuel to the injector rail with an external fuel pump. The van would not start, so they recommended it had a new high pressure fuel pump and new injectors, they suggested sending it to a diesel specialist.
I had the van recovered to my home and arranged for a mechanic to change the high pressure fuel pump, including the timing belt and water pump.
Due to excessive cranking the starter motor failed, so have also replaced the starter and a new battery. The van still won’t start but will fire with easystart.
It seems like no fuel is getting to the engine, so believe there is an electrical fault which is behind the issue. I have visually checked all fuses and all electric connections look fine, but have limited expertise in this area.
The van has been tested with a launch diagnostic code reader and no faults are evident other than ……….05FF unexpected realisation fault coming from Bsi, however I have been told this is quite normal.

I really don’t know what to do next, so I would be grateful if anyone has any clue what the problem might be?