Hmm that isn't good at all. AFAIK NTL is supposed to be one of the few ISP's in the UK who don't shape p2p bandwidth or block p2p programs.

Is your OSX firewall turned on? If yes, then you should configure it OSX Firewall settings for Tiger (click on link).

What brand & model of modem/router are you connected through?

Do you see all green connection bars or are some red at the bottom of LW's window?

Try one of the video files from the magnet site.