The Furniture Re-use Network (FRN) is a national body which supports re-use organisations throughout the UK. They have a map of re-use charities.

Charity shops will take reasonable items of furniture, but not beds, for hygiene reasons. Items must have the kite mark indicating they meet British safety standards.

Oxfam have specialist furniture shops.

Try local homeless charities as well – they may need beds and mattresses too.