I too live in England and am on a very tight budget and have got some gorgeous bedding from Boot fairs for next to nothing, the most i've paid for a double duvet cover sheet and pillow cases are £3 for the set, also put a request on Freecycle / Freegle, or Gumtree and watch for people giving them away., last week i got some lovely stuff suitable for quilt backs, all they need is a freshen up, good luck am sure you'll find things,