Great responses thanks guys. I'll get a dri-fit hoody (without the hood) and a couple of dri-fit t shirts to rotate; I'll wash them every few days I reckon.
Mind you, there's probably little point, seeing as I woke up on my first morning of the last trip with all my thermals floating in the bath, because I was incorrectly blamed for stuffing my mate's boots full of snow.
..which would in itself have been entirely reasonable, considering they tricked me into thinking that (having flown out a day late) my plane tickets had been sold; and then they left me standing out in the snow for over an hour at 2300 in Val d'isere, having told me the flat was being fumugated for rodents.
Bunch of c*nts.