Yes, the dealership will take the vehicle in for another look (they had it for two weeks last time) and will provide a loaner.

Bye the way, I am a big BMW fan and this is my third car - the others were a 320i and a 330xi. I also own two BMW motorcycles - both R1200RTs... The one thing that I depend upon since I travel extensively around North America is a reliable mode of transportation. Never before have I received a different answers from every person that I have interacted with in the service department. The original failure did act like a frozen/plugged differential or a simple overfill, but since it was only -1C at the time and had barely been driven (300Km) I was simply shocked.

I will report back after this service outcome - hopefully there is some simple explanation for the re-occurrence of the issue. There can be no doubt that if this is a vehicle that cannot be driven in winter I will have to find a replacement that can... as unfortunate (for me) as that is.

Stay tuned.