Most likely due to you using Tiscali services who are reknown for shaping p2p sharing bandwidth. One alternative, though it might not work is to change both your listening & connection ports to a higher number like between: (49152 - 65535). Go to LW's menu bar, Tools -> Options -> Firewall, & you will see the options.

Check Tiscali on this list: ISP's known to BLOCK or Filter p2p or specifically Limewire (Click on blue link)

After Tiscali walked into UK, they have taken over many UK ISP's, even if the original company retains its original name. Difficult to find non-p2p shaping bandwidth/blocking ISP's in UK nowadays.