Your ISP is known for shaping p2p use during peak times....
Quote from Fair Use Policy...
8. Does this mean I can’t use Peer-to-Peer (P2P) applications?
No, we are not stopping people using any P2P service. We are simply ensuring that bandwidth is shared fairly between all customers at peak times, generally in the evenings. Outside of these times P2P will have full bandwidth access. It is worth noting that P2P is not a time-sensitive application.
A minority of users (around 2%) far exceed all others in terms of bandwidth demand, some using 600 GB per month. We have taken the decision to limit bandwidth available to these users at peak times.
Broadband Usage
You could also try Port Forwarding, this will enable limewire to pass through your routers Nat Firewall..
These are your instructions...
Port Forwarding for the BT Home Hub