Thank you for your reply.
What about the oil on and around the rocker cover? Is this a sign of a blown turbo or is it a minor symptom of the leaking air hose. I am pretty sure the oil did not come from the filler cap.
What about the "i" warning light which is lit (the one between the temperature and fuel gauge. Does it need to be reset by a main dealer or does it go out by iteslf once the fault has been repaired?