As an aside to that quirk of BT's service:
We're on a crappy wired connection here speed wise but noted the other night that next door's WiFi signal is not far off as strong as ours.
After a bit of time in the old interweb I came across a utility called Connectivity Dispatch PRO:
Seems it pulls together all available wireless internet connections and increases your speed. Paid for unfortunately but it got me thinking. My boy, on his desktop is always whinging about the speed of his wired connection, having left behind a super fast Virgin connection at his uni digs. I wonder if, with a wireless WiFi adapter plugged in he could combine next door's WiFi? Ideally with a free utility!