Turbo, Injector and boost faults

[JimmyG123]

Been having problems with my 2007 BKP 133k Passat B6 Estate.
Bit of background, had it since early 2018, oil pump went end of 2022 but managed to pull over straight away so didn't cause any damage to the engine.
Started in January when it died on the way to work, loads of white smoke out of the back and noisy engine.

Here is the scan that was pulled straight after... Please Login or Register to see this code
Pulled over straight away and got it towed to my mechanic, turbo had got so got a re-conditioned one and had it replaced.

Afterwards I was still getting the PD Unit Injector: Regulation Range Exceeded - Intermittent fault on cylinders 1, 3 and 4.
Along with the boost pressure regulation fault intermittently, mainly when driving up hill in low gears. Small amount of smoke out of exhaust.
My mechanic checked the wiring from the ECU to the injectors, replaced seals on injectors and replaced injector wiring loom.
Fuel filter was dirty so that was cleaned out and replaced.
Still the same issues, he then switched injectors 2 and 3 over and the fault moved to cylinder 2.

Probably should have given up here but decided to keep going.

Bought 4 re-manufactured injectors, which were installed.
Now only had the Injector fault on cylinder 2, and the intermittent boost fault.
We figured the one of the injectors must have been faulty so we replaced it with the one of the original 4 which was not throwing up the fault code.

Now after quite a few drives we have no injector faults at all and definitely more power than before. Sounds good on idle and when coasting but quite lumpy/juddery engine when accelerating. Kicks in at around 1500rpm.

The only fault I am getting now is...
Please Login or Register to see this code Does anyone have any ideas what could be causing this?
Seems like other on the forum with this issue have vacuum leaks or swirl flap/inlet manifold issues.