Oh..forgot to mention...
I thought I had a bad cylinder head. Believing that the guides were worn. Even though I had stem seals, valves lapped, skim and test at a machine shop. Reason was, it was smoking at startup and oil was pooling on the pistons when the engine had cooled.
Turns out... I think... it was actually the turbo. When the seals went (probably been going for a while) it has been dumping oil in the inlet tract.
I cleared it out, as best as I could - but never removed the intercooler fully for a clean. Using a bore scope, I checked inside the pipework and could see oil still in there. It was also weeping in the throttle body. So it had literally been everywhere.
Cleaned it all out with acetone.
and.... no smoke!
Whether it was 100% that, or maybe 50% or 75% I guess I will see. But it is noticeably different now, when it starts up - hardly anything and no misfire.