where can i get a rdeamcast and shenmue in the uk
Try Gamestation or any shop where they sell second hand video games/consoles. Look out for them in town markets/car boot sales, or look on ebay.
I have a Dreamcast you could have if you wanted. I dont know where you could get Shenmue though, It seems to be a very rare find in Game shops now and pricey on the web (Or is that the sequel, or both?).
I saw a DC for 20 bucks at a pawn shop...dunno if you have one of those around your area, though.