I think the new cam sensor and bleed off pipes have helped a bit, but it is still hard to start/restart and cuts out the engine on a frequent basis.
So this morning I got 4 yogurt pots and some hose, stuck them on the injector bleed off ports and ran the engine to look at bleed off rates for the different injectors. I was going to be scientific and run it on idle for a couple of mins and then alternate high revs/idle a few times then measure the amount, but after less than a minute at idle, one of the pots was almost full! Numbering left to right when facing the car, No.1 was the best, just a small amount in the pot. No. 2 was bad, a half filled pot, No. 3 was about a quarter full and No. 4 was almost a full pot.
So it looks like the garage's suggestion was right, it is the injectors bleeding off too much fuel so the high pressure cannot be maintained in the common rail.
Anyone know where I can get some cheap injectors and if I need to get the new injectors registered with the ECU?