So I bought the official Audi cool box that works off the 12V supply. (Part number 4L0 065 402.) It's a nice addition to the car especially as we prepare our own baby food which really needs to be kept cool on hot summer days if it is going to last the day without starting to ferment!

Regarding mounting it, I remember seeing an official Audi parts book that shows there is some sort of harness available that stretches around the box to hold it in place, and clips into the plastic moulding around the boot of the car. However I cannot find a part number for this anywhere. Anyone know?