How is “stand in” used?

In Signed, Sealed, Delivered: The Vows We Have Made (2021), one line is: “standing in the London Museum of Mail,”

Which movie is “stand in” from?

The clip at the top of this page is from Signed, Sealed, Delivered: The Vows We Have Made (2021).

to block or hinder someone from doing something; to judge someone or pass judgment on them; to wait one's turn in a queue; to take sb's place

Heard in 92 movies

Editorial25% of films
to block or hinder someone from doing something
And I will let nothing stand in our way.
Why did you stand in my way?
Editorial5% of films
to judge someone or pass judgment on them
Editorial5% of films
to wait one's turn in a queue
Oxford5% of films
to take sb's place

Definitions from the Oxford Advanced Learner's Dictionary, 9th edition

standing in the London Museum of Mail,

Said in 8 films · #1