this is from wikipedia so not sure if its 100%
but makes sense
"Filming
Several scenes from this episode and "Silence in the Library" were filmed at Swansea's Brangwyn Hall. These include the library reception area where the TARDIS arrives, and the staircase where the Doctor and Donna look out over the empty library. The climactic scenes of the episode (in the library core) were filmed in an electrical substation of a disused Alcoa factory in Waunarlwydd, Swansea.[7] Other scenes were filmed at the Old Swansea Central Library[8]
Scenes set with CAL's Databanks were filmed at Dyffryn Gardens, St Nicholas.[9]
The wedding dress Catherine Tate wears in this episode is the same dress she wore in "The Runaway Bride".[7]"