got a second opinion from a mate at another vw dealership. Cars been check out again, found no issues, faults or damage. However, the engine oil level was slightly too full. I'm told not enough to cause any damage, but it could explain the smoke from the exhausts. Simply burning off the oil. So being a lovely chap he very kindly drained a wee bit off.

I know too much oil can cause BIG problems, but he reckons it was only slightly too much and no damage has been caused.

So after all that, it turns out that I was the culprit, slightly overfilling the oil.
Oooops, bit of a school boy error :embarassed: