Well, the DD GF4 block, I think dtek sells one or two, Swifty's two, but for you in the UK I'd go with the Atlantis line. Oh, and Innovatek's GF4 block. It's pretty nice, I've got both the Innovatek NB & GF4 (Ti4200 128MB), and it works good. Not too expensive, small, but 3/8 OD, 1/4 ID. You should see the ghetto T i made out of brass for these blocks to work.