*moved to WC section*
I would start with Swiftec's current LGA775 offering, for straight water cooling (sorry, don't know the exact part number, but shouldn't be hard to find). I'm sure you will be able to pick one up within the UK. From there, I would recommend a double heater core w/ dual-120mm fans for heat dissipation. If you can't get heater cores in the UK, then the H120.3 is comparable, in terms of performance, but costs substantially more. For a pump, you can either go with the Danner Mag3 (cost-effective, but requires sealing the shaft, if running non-submerged) or the MCP650 (also Swiftec's...costs 2-3x the Mag3). And don't forget tubing (cheapo stuff can be picked up from a local hardware store....1/2" ID all the way, baby) and clamps (here again, your local hardward store will have metal clamps).