Cheers Clarky, I knew some things were going to need doing (cambelt, DSG service) but I hadn't expected her to dump coolant all over the garage after i'd driver her back from the dealer who was quite a way away. I'd already walked away from one that day and talked myself into getting this one ('only' 81k on the clock and on the surface in moderate condition plus some nice extras).
The guy who did the cam belt was proper puzzled as he couldn't find a coolant leak even under pressure. Turned out to be a too small seal and it only leaked as the system cooled down!
Now to figure out why the boot is wet...