I finally managed to get hold of a technician who explained that their transmitter is undergoing maintenance, and is expected to be back in operation within a few days.
BBS has a few venues for disseminating information about outages: BBS TV, BBS Radio, the BBS website, the BBS Facebook page, and BBS twitter page. Let's hope these will be used in the future.
PS: BBS live streaming, which was set up just before the royal wedding, is also dead.
Update (26/10/2011): Transmitter is now back to service. Just in time for Diwali!