If your downloading at full whack from gamefiles.blueyonder.co.uk then it could be a Virgin Media routing connection, speedtest.net isnt a good tool to use, if you arent getting full whack speed from gamefiles.blueyonder.co.uk, then you need to either post on the Virgin Media newsgroups, if not then nothing you can really do, remmeber other sites will only give you the speed its servers can handle so remmeber if there server is 10Mb and its busy your gonna expericnce slow speeds also try open dns
http://www.opendns.com/ this should help with the slow browsing