Off tangential interest, filming on Sherlock Series 3 has been pushed to March 2013. I'm not surprised by this. Reshoots on The Hobbit were scheduled for after the New Year, and a two month delay makes Martin Freeman available for them. Plus, a two month delay in filming gives Steven Moffat some downtime between the end of filming on Doctor Who and the start of Sherlock. My guess is that The Hobbit was the main factor in the decision, though I'm sure Moffat isn't complaining. Will this have an effect on Doctor Who filming in 2013? Perhaps.