[paultyler1]

Late update on this posting. I had the car repaired - new turbo, cat and dpf plus other bits. 7000€!! It should be borne in mind that I live in rural France so trying to find a good independent is impossible so it was main dealer or nothing. Anyway, the repair was completed last September. Up until a few days ago all was ok but now the problem has returned. Lots of white smoke for a few miles and then nothing. I've tried "booting" it on the motorway - no smoke whatever. Also, nothing if I go downhill with no throttle and then accelerate hard.
I've held a white cloth over the exhaust and there are no oil spots from the exhaust gases. The "smoke" doesn't smell of burnt oil and I wonder if it's water vapour. On this point, the car does lose water (about a litre every 400kms) but the level does drop overnight. There are no obvious leaks either underneath or from the heater matrix inside. I wonder whether, somehow, water is leaking into the turbo and when the engine is first started the water vapourises. Is this possible? Wouldn't this have been cured with the new turbo?
Any comments greatfully received, the earliest the dealer can see the car is the 8 February.