Much of the dialogue here has been replaced in post-production, especially in scenes around the transport vehicle - where lines are "spoken" by actors who are facing away from the camera, moving rapidly across the shot, or just not visible at all.
As of December 2023 , this episode has the lowest IMDB user rating of any Doctor Who episode, including the original Doctor Who (1963) series.
The cat-human character calls herself "Hyphen with a 3". The script and subtitles write this as "Hyph3n" and the character explains the 3 is between the second h and n when questioned by The Doctor, but it could also be written as "-3", ":-3" being an emoticon for a cat's face.
Hyph3n's make up and costume design resemble the character played by John Candy in 'Spaceballs.' John Hurt (The War Doctor) had a cameo in that film, essentially reprising his role from 'Alien.'