The Royal Mews are the royal stables at Buckingham Palace in Westminster, a database landmark in Syndicate.
Prince Albert added a forge and cow sheds, and in 1855 Victoria paid for a school for the stable staff's children.
The Mews is a database entry attached to the Buckingham Palace grounds in Westminster. The palace itself hosts the Queen's ball in the final memories, so you pass this area during the endgame.
10 Downing Street
10 Downing Street is the Prime Minister's home and office in Westminster. In 1868 Benjamin Disraeli lives here, and Jacob's work as his bodyguard in Sequence 7 starts outside the house.
Admiralty
The Admiralty is a government office on Whitehall in Westminster, one of the period buildings you can climb and read about in the in-game database. No memory centres on it.
Banqueting Hall
The Banqueting Hall, later the Chapel Royal, is a 1622 hall on Whitehall in Westminster and a database landmark in Syndicate. It is the only surviving part of the old Palace of Whitehall.
Blue Anchor Alley
Blue Anchor Alley is a Blighter stronghold in Westminster run under Lilla Graves, one of two in that borough. Freeing it lets the Rooks set up there instead.