I live in Cheshire (I think about an hour from sheffield) and I am more than willing to provide some mature sponges if you could give me some replactment ones (the bacteria will re-colonise in about a day) but I guess it depends on if you can travel as I cant deliver.
I see, very annoying cos its one of the only things in the fishkeeping hobby that cant be sent in the post (even fish can be sent!), hopefully someone will be close enough
Good luck