Doctor Who: 14 Cool Details Revealed In David Tennant's The End Of Time Part One Commentary
3. These Stables Were Used In The Next Doctor...
More familiar locations! The scene where the TARDIS materialises inside a stable was also filmed at Tredegar House, and as pointed out by Tennant, we've seen these stables in a previous Doctor Who episode: 2008's Christmas special, The Next Doctor.
The scene in the image below (where the Doctor reveals the truth about Jackson Lake's past) was filmed in pretty much the exact same spot where the TARDIS lands in The End Of Time Part One. Outside the Doctor Who bubble, the Tredegar House stables were also used in the Torchwood episode Something Borrowed.
Tennant adds that he didn't really like this stable location very much, because he's a tiny bit allergic to horses. At least he managed to hide that on camera.