Sonic State has an exclusive behind the scenes documentary from Bang, the post-production house in Wales responsible for the sound for the Dr Who series.
This first video is an introduction to the facility and their equipment/resources.
There is a short intro to the world of foley.
Following episdoes promise a more in depth look at sound design and foley - so should be good.
The second episode is now available. The majority of this post discusses their new Dolby licenced 5.1 studio. There are also a few comments from Russel T Davies (the main producer of ther series)