If watercooling is what you would like to try next, see if our very own Dave Hutchinson can help you choose the right kit... See what he thinks of the Aseteks latest WC kit here!
50 pounds? jesus, they're overpricing that block, arent they... The mcw6000 block performs better than that at lower flow rates, and is 40odd US
http://www.thecoolingshop.com/product_info.php/manufacturers_id/120/products_id/875 £30+VAT free delivery if you;re willing to bolt the block together yourself. £37+VAT assembled