I'm having the same issue, with my phone working just fine. Since early in the morning, my DSL light won't turn on. I'm on a HH3, and have done the whole disconnect reconnect rigmarole. I'm in the Sheffield area.
anything here http://usertools.plus.net/exchanges/mso.php
Mine went down in the early hours of yesterday morning. Seems to be working first thing this morning. Currently at work, so can't say if it's still holding up. It was apparently down to a 'network issue'. May possibly be the same for you.
Lo' and behold...it works again this morning (despite BT telling me it was fixed at 1PM yesterday when it clearly was not).