Ok so its running again, dunno why, went out to try again and it fired right up, gave it a blast around the block to try and recreate the symptom, which it did, went into limp mode, then cut out, fuel pressure was ok till it cut out (at a guess 4000 psi, I was driving) then showed 87 psi keeping it it rolling and flicked the key off/on normal again.

Pushing it as much as I dare down the lane it got up to 18000 + psi, dont know if this is too high or not but it does look about right at a guess

Got it into limp mode again, drove home and its idling nicely now, restarted it and its all ok with a nice idle, weird.

Codes are ...

P1211, Injector control pressure Higher/Lower than desired
P2291, Injector control pressure Too low - Engine cranking

The fuel pressure is holding with the engine off, so will check this again tomorrow to see if any of the injectors are leaking down.