A short cut, I did an ip check & it appears your ISP is TISCALI UK. Now they are the worst ISP in UK however they control many smaller ISP's under them unfortunately.

Check for options here: ISP's known to BLOCK or Filter p2p or specifically Limewire (click the links under Tiscali)

BTW this is an important note about their rules: Tiscali - Fair usage policy
Quote: "If on the other hand they are using Peer to Peer or file sharing software they will experience slow broadband speed."
(This can also affect connections.)