I got no further with this, but have a couple more questions
The smoke from exhaust is mostly when its idling, so;
Could the oil feed to the turbo,create this smoke at idle?
If the PCV/CCV valve is blocked/dirty, would this create a smoky exhaust at idle??
Im now thinking that the turbo is not a problem, possibly too much pressure/blowby from a worn engine is creating the smoke.
Does this sound feasible?
I really need to get the emissions down for an MOT test soon