> TIL Scotland Yard is the Metropolitan Police.
It is not? But also it is.
You are right that when people say "Scotland Yard" they do frequently mean the whole Metropolitan Police. And you are also right that there is no other police entity (that I know of) which would be associated with that name.
But also, "Scotland Yard" was just the address of the original headquarters of the Metropolitan Police. Even then it wasn't the whole organisation, just the address of one of the buildings. Then they got a new headquarters and called it "New Scotland Yard". And to confuse matters further they repeated this multiple times. Which means there are 3 buildings which were called "New Scotland Yard" at various points in time.
And today of course the MET occupies far more real estate than just the famous "Scotland Yard". For example if you look at this FOI request[1] you can see that there were 226 other buildings the Metropolitan Police used in 2023. (Not counting covert/sensitive estate).
1: https://www.met.police.uk/foi-ai/metropolitan-police/disclos...
Scotland Yard was originally the name of the street in which headquaters of the Metropolitan Police.