Car is fixed!
the split boost pipe clogged the DPF beyond regen being possible.
Bought opcom/vauxcom diagnostic kit for the laptop, it read 255% soot accumulation and said 170km since last regen.
I was able to trigger an active regeneration on the driveway and the car went nuts, took it to 3.5k rpm and held it there for about ten minutes, it filled the entire street with smoke, and then when it cleared up, the process finished, and car has mega boost again. Spins front wheels in 2nd gear if you floor it.
Thanks to everyone for your help, I think I’ve doubled my car knowledge in the last week.