Best Water Cooling Kit For Around £100

Yup, I use Specialtech, great service,
The Ex rad in the kit Adam linked is better than the Rs rad in your first kit, and the 240 kit is better than that, bigger rad and better block, although the Ex rads are better performing than Rs's, the increased size is the bonus there,
Heres a list of online retailers, I contributed most of the UK ones as I have used them and have had no problems
http://www.tomshardware.co.uk/forum/277130-11-read-first-watercooling-sticky
Its part of the W/c sticky,
http://www.tomshardware.co.uk/forum/277130-11-read-first-watercooling-sticky
and if you make another thread concerning this, please put it in the W/c section of overclocking, more of us frequent it and will be able to help
Moto
 

DeusAres

Distinguished
I honestly don't know. I'm not from the UK. Sorry. :(

However, they appear to be safe. It's one of the first links that appeared when I searched for those kits in your area. You may be able to find 'em on other websites such as amazon.co.uk.