The lead role was initially written for a man, until Andrea Riseborough came in and read for one of the other parts and challenged the producers to make the lead character a woman.
When Mia (Andrea Riseborough) is in the kitchen making coffee for Shazia (Kiran Sonia Sawar), she stares thoughtfully at a block of brightly colored kitchen knives for a moment. In real life these knives are of a brand called Taylor's Eye Witness; a subtle reference to the theme of the story.
In the hotel where Mia (Andrea Riseborough) was staying the hotel management has made very strict rules since an incident with a judge of Hot Shots. Hot Shots is the TV show where Bing tries to get Abi to sing on season 1, episode 2, Fifteen Million Merits (2011).
The song DC Lydon (James Eeles) heard on the street, and the song Shazia Akhand (Kiran Sonia Sawar) sings in her car is the same song that Beth sings at karaoke in the "White Christmas (2014)" episode, which is the same song that Abi Kahn sings in the "Fifteen Million Merits (2011)" episode. The song is "Anyone Who Knows What Love Is (Will Understand)", recorded by Irma Thomas in 1964.