Wycombe Caves
From Tardis Wiki, the free Doctor Who reference
Wycombe Caves was a cave system in Buckinghamshire. It was used as a base by the Hellfire Club in the 18th century.
In 1806, the Eighth Doctor and Charley Pollard visited the caves in pursuit of Sebastian Grayle, where he succeeded in bringing the Nimon to Earth. (AUDIO: Seasons of Fear [+]Loading...["Seasons of Fear (audio story)"])
