Ok, so the lastest from the dealer is... they’re going to get the turbo completely rebuilt, Remove the head and completely clean that out and see if or what need doing and complete flush and clean of all air intake and intercooler flush!
Unbelievable really. Taking complete ownership of the situation and suplying a car for me in the meantime.
Can’t ask more than that from a used car dealer who has no warranty obligation to do anything at all.
Might go buy a lotto ticket!