I spoke to someone in BT Edinburgh who said it might be also related to the 6.1.1.R firmware update. Mine was upgraded from 6.1.1.M, without so much as a by your leave from me, and stopped working. It was designed to fix a bug in IE7 for Vista, and has borked the entire network. They may/will have to issue a retrograde to unfix this new "feature".
Talk about annoyed. I got the run around from a "technical service officer" and ended up trying to diagnose the problem myself. I tried dcc in OS X and Fedora Core Linux to locate the problem to the router or the network. I thought I might have changed something in a firewall etc, so I reset the router and put it back to "factory", but still with 6.1.1.R.
It is ridiculous that we have no control over automatic "upgrades". They should issue a new firmware patch, which allows you to TURN OFF upgrades, from the web interface.
So it may take a while to get sorted. I think we should get a class action for damages going. I lost my Sunday off due to this utter BS from BT.
Your 'umble servant, gordboy