Mine does the same ticking over when cold. I have changed the injectors, glow plugs, and turbo. Still the same - especially in winter. Not quite such a cloud, but it does accumulate a lot of blue/grey smoke. I doubt its the head gasket. Is it using a lot of oil? Mine has never drank oil, and to be honest, doesn't seem to use any more than normal, and doesn't need topping up much between changes! I have put it down to something to do with the inlet and egr system. The van runs sweet as a nut. Especially when warm, and does not smoke. Except occasionally under light acceleration, but even then, its only slight. It does get its legs stretched every time I drive it - not thrashed, but driven 'properly' for an oil burner
I would replace that turbo though, as the impellers do look very worn. Good luck pal, and keep the thread updated! All the best,
K