We get them in Sheffield on The Moor. Normally its NSPCC or Shelter.
I have nothing against these charities, but I dont like it when they bound over to me and say 'hi mate'. Im not your mate, piss off. If I want to give to charity (which I do anyway to Cancer Research UK), id approach them.
However I must say that The Big Issue sellers are very polite. Theres a couple I see regular and if you say 'no thanks' the usual reply is 'thank you, have a good day'.