At last, something that MIGHT fix my problems.
I got the call from the service manager today advising they will be replacing most of the engine (bottom end, pistons, etc). The parts come in tomorrow and the car should come back to me by the end of next week. Fingers crossed this fixes my cylinder N04 issues, oil consumption and soot/oil splatter on the hatch.
This is the repair that SHOULD have happened in December 2012.