I got it from Decathlon in Stockport in their sale. It's actually a women's XL, but there's no difference in cut to the men's other than size. It equates to a men's medium. They had some men's for twenty pounds, but they were red (not my colour), and the mix was fifty fifty down and feather. I figured it was a better deal paying a bit more for a much better down content.
They do some great deals in Decathlon sales. Last week I picked up a couple of life vests for canoeing. They should have been fifty pounds each, but were selling for six.