From TARDIS Index File, the free Doctor Who reference.

Little Caldwell was a village in the Berkshire region of England, not far from the town of Newbury. (NA: Return of the Living Dad) It was located near an American Air Force base, USAF Greenham Common, where the Doctor was once imprisoned and tortured. (NA:The Left-Handed Hummingbird)

Little Caldwell was home to "The Pyramid", a combination coffee shop and book shop that was also, secretly, a safe house for aliens and the temporally stranded. (NA: Return of the Living Dad)