Despite the fact that the story takes place over a month after the Battle of Lexington and Concord, which began the American Revolution, King George speaks of "rumors of insurrection in America". Since news traveled slowly between the Americas and Europe (a sea voyage requiring 6 weeks was common), it is not surprising that word of the fighting had yet to reach the King.
The prisoners are pressed by the Navy for HMS Defiant. There has never been a Defiant on the Royal Navy List, but there have been two fictional ships of that name: The frigate HMS Defiant in Damn the Defiant! (1962) and the starship USS Defiant in The Tholian Web (1968).