A few interesting observations: 1) The fairground caretaker was played by Brian Miller,who was Elizabeth Sladen's husband. 2) This episode marked the first instance of Classic Who clips - with accompanying audio - being used in any story from the revived era. (The Next Doctor also contained Classic clips,but they were mute). This looking back to the series earlier history becomes increasingly frequent. 3) This episode marks the first appearance of the TARDIS in any Who spin-off.