i thought BT blocked torrents during the day
No, they've never blocked torrents / Peer to Peer, but they do traffic manage certain types of traffic.
However you can disguise the way uTorrent (etc) send / recieve the data so their traffic management systems don't know it's peer to peer, so it never slows down
BT Infinity #2 - 8.7MBps via P2P ¦ Full 80/20 Sync ¦
BT / Openreach - You've finally done well. Very well indeed.