Sorry, but Talk Talk customers have a lot of problems. Have a look at these threads below. If you use the forum search to look for Talk Talk, you'll probably find more threads

Is that it then, TalkTalk

ISP's known to BLOCK or Filter p2p or specifically Limewire

1-3k downloads

ISPs that throttle p2p - The Scream!

You could try changing ports but there's no guarantee that it's going to help you. In LW tools > options > advanced > firewall config. Change LW's listening port to 64049 (or something in the range of 49152 - 65535) > Apply > ok.