In LW go tools > options > advanced > firewall config. Change LW's listening port to something in the range of 49152 - 65535 (eg 65000) > apply > ok.
You can try any ports in that range.

Your ISP say that they don't throttle p2p & I can't find anything to suggest that they do. Have you tried using LW outside of peak hours?

You could also try the advice here (the first few posts by murasame), if you haven't already.
A few things to consider while configuring Limewire for optimal performance...

Posts merged onto existing thread.

thanx birdy, i have tried limewire outside the peaktime, but i have the same speed issue! i downloaded frostwire, just to see if i have the same problem in that & again the connection had a brick wall...

i even tried utorrent & i am having speed issues with that too!

everything worked fine on my pc, until the day i migrated to a new ISP, i am recieving upto 5.5mbp down my phone line, but it seems like anything i use p2p related is more like dial up speeds!

could this problem have anything to do with my modem? i am using the same usb adsl modem provided to me, by my previouse ISP, fast.co.uk did not provide me with a modem.

could there be a compatibilty issue? that brick wall was not in limewire until the day i changed my ISP, so i am guessing it is either my modem, or my ISP...

would it help if i changed port in limewire?

appreciate any advice! thanx