Well you should be getting faster speeds. But TalkTalk "is" the problem. Have a look here ISP's known to BLOCK or Filter p2p or specifically Limewire, there was a no. of people using TalkTalk who were having the same problem. Answer? Look around for other isp's. There's a link in the above link which is a guideline for those isp's known to either block or shape bandwidth for p2p use in the UK (at the bottom of the 1st post.)

eg: Another member on the forum posted a snapshot of his speeds from the same magnet link site & he was getting over 200 KB/s from memory. You 'should' be getting up around the 100 KB/s I should imagine.