. Warm: That and a T-shirt did me (for period ups to half an hour) for all but the most bonecrushing of the winter.
. Light: That, unzipped, and a T-shirt did me through most of the summer (NB I might not have been in serious direct sunshine for half an hour because hello, London). Also I can cycle in it, though I might have to wash it shortly afterwards.
. Light(2): fits into 1/2 my backpack (er, is that the word I mean? The only other name I can think of is shoulder-bag, which sounds to me like one of those long-strap things that the nearly-young folk wear)
. That's it.
So, wise people of the internet, where would I go to look for these? My budget is whatever the previous one cost, though I don't actually know since it was a Christmas present from, er, my mum (have I mentioned shut up yet?)