Wee update on this.
Swapped out the crap imported cast manifold and reinstalled the OEM one, along with new gaskets, turbo-mani bolts, nordlocks, and new mani-head nuts. Installation went a breeze and got rid of the fumes in the engine bay.
However....
There was now noise from the DP area, had it in to the local exhaust place for a swatch on their ramps, sodding weld at the flexi joint has gone on the turbo side.
Dunno if I'll be able to patch it or get it welded, wouldn't mind but it'll be the thick end of £500 for a new 3" Milltek DP with 200 cell cat!
feck me.....