This note from a worker at Osterley Park accompanied the photograph.
"Osterley Park is the inside of the Wayne Manor. That's right 3 rooms - dining room, and study - we forgot to ask what the 3rd room was - it was mentioned the study has a secret exit that will lead to the Batcave. Technically we are guaranteed sighting of Alfred (Michael Caine), Bruce Wayne (Christian Bale), I think Anne Hathaway, as she's likely to be having dinner with Bruce. There is a secret door in the study from which Wayne will escape."
The Dark Knight Rises was released July 20th, 2012 and stars Tom Hardy, Christian Bale, Anne Hathaway, Liam Neeson, Joseph Gordon-Levitt, Gary Oldman, Marion Cotillard, Morgan Freeman. The film is directed by Christopher Nolan.