After a lucky chat with a mate I have tried a known working maf and the issue returns with that installed and plugged in.
Suspect sticking egr now.
Will see about getting it mapped out.
I hope that solves it otherwise it’s loom failure.

If you’ve already blanked off the egr and it made no difference what’s the point of mapping it out?

How I have come to understand it.
Blanking just prevents exhaust gases in the combustion resulting in cleaner burn.
If egr is faulty the ecm is still recieving position information and if these are outside the acceptaple parameters eg the valve is stuck open. Ecm will adjust. Shutting off boost.
I will have it mapped out and test theory.

Egr mapped out and all is well. Boosts much better and more responsive.