Hi Dave,
I thought as much when I saw your 1st post of this thread -- your problem is your ISP TISCALI - they are known to throttle P2P see
this link for ISP's known to Block P2p or specifically Limewire.
Have a look at this link
I have found a solution to getting Limewire to work with Tiscali
Are you using the paid version of AVG -- if so good this includes a firewall -- if not you have no firewall -- if you have a firewall please enable it.