The green police box mentioned towards the end actually exists and is on Surrey street in Sheffield, as said.
The custard cream dispenser was described as a little gift for Jodie Whittaker from the set designers. The head Art Designer, Arwel Jones, asked Whittaker what her favorite biscuit was and installed the dispenser as a surprise for her.
Epzo tells Angstrom she's "nothing". The angstrom (properly spelled "ångström" but in English the Swedish special characters are often left off) is an incredibly tiny unit of length, 0.1 billionths of a meter, which is almost nothing. The distance between the two carbon atoms in acetylene is 1.2 angstroms and each carbon-hydrogen distance is about one angstrom.
During a confrontation between Angstrom and Epzo, The Doctor uses a 'Venusian Akido' technique to paralyze Epzo. This fictional martial art was introduced during Jon Pertwee's tenure in Doctor Who (1963), and featured on more recent occasions, such as Robot of Sherwood (2014) and World Enough and Time (2017).
Someone has said "Don't panic!" in each episode this season. This is the tagline of the Douglas Adams book and dramatizations "The Hitchhiker's Guide to the Galaxy". Adams was a writer and script editor on the original Doctor Who (1963).