Shireen refers to 11 Cardinal Road as "a freaky Scooby-Doo house". The episode was partly filmed on location on the same property used for Wester Drumlins in Blink (2007) - in which a character also referred to the place as "Scooby-Doo's House" - and in Last Christmas (2014). David Suchet stated he "completely freaked" when he realized on the third day of filming that his family had rented exactly the same house the Christmas before for the holidays.
The Doctor asks the Landlord who the Prime Minister is and rattles off a list of names, including Harriet Jones, a fictional PM from some Ninth and Tenth Doctor stories.
The Haunted Hub was erroneously reported as a working title.
David Suchet said in The Fan Show: The Aftershow that he used a real life experience of being covered in woodlice for the scene where the Dryads come crawling all over the Landlord.
The Doctor's observation that "sleep is for tortoises" is a reference to The Talons of Weng-Chiang: Part Three (1977) in which the Fourth Doctor said the same thing.