Hi!
I am not sure what they will sell for in the UK but here in the US the uprights don't sell for very much. Depending on who made it can make a matter of dollars. Can you look inside the top/back and the name of the maker should be on the metal plate and tell us who it is? Does it have the original ivory keys? What shape are they in?
Many people are buying them to 1) play the piano, 2) turn into : bookcases, bars, aquariums, desks, Hideaway beds, etc. I have even seen a baby grand made into a garden planter with water flowing over the keys! :O