TK Maxx. A bit of a random selection but you'll find everything from socks, thermals, salopettes to beanies
Mountain Warehouse is good too - think they have an end of season sale on at the mo as well
Anyone know of reasonably priced place to by ski clothing for my 12 year old?
Given that kids ski stuff gets grown out of before barely worn, perhaps some good folk here could pm you and help you out for the price of a few beers?
Or try eBay?
I'm amazed nobody's mentioned Lidl or Aldi. Both had ski stuff in a month ago, and our Aldi currently has loads of the stuff reduced in price.