Berkshire
From Tardis Wiki, the free Doctor Who reference
Berkshire was an English county. The village of Little Caldwell was located there, as was the town of Newbury. (PROSE: Return of the Living Dad)
Behind the scenes
Stargroves estate in Berkshire was used for the exteriors of the Victorian manor house in TV: Pyramids of Mars.
Real World Locations
Though it's possible that the following locations don't exist in the same geographic space in the Doctor Who universe, such cases are few and far between. Therefore, the following towns and cities are probably located within the county of Berkshire.
Bracknell | Crowthorne | Earley | Eton | Hungerford | Maidenhead | Newbury | Reading | Sandhurst | Slough | Thatcham | Windsor | Wokingham | Woodley |