oh well theres always a bit of discussion over hear because we get the grannies/teeth programs often on the digital BBC channels, and you think, er, why? As in why do that at all when you could be producing stuff like LOM. ANyways.
Over at the guardian theres a full explanation/interview with the writers, should you want to read it
http://www.guardian.co.uk/tv-and-radio/tvandradioblog/2010/may/21/ashes-to-ashes-final-episode