I attempted to be a donate many years ago. Went twice and had a bad reaction both times so not allowed back. Having lived in Europe for a couple of decades now would be off the list anyway.

Not taking blood from people who have lived in Europe is actually good science as there are problems with disease here that go beyond mad cow that are behind it. Europe (not just the U.K.) has to import a lot of blood products as they cannot use local supplies for this reason.