Russell casually revealed that Episode 7 of Series 14 (which won't air until Spring 2024!) is set in America in 1947
We've already seen it confirmed that Series 14 begins airing on Christmas Eve, so the only way that airdate works is if the show airs four or so episodes of Series 14 and then goes on hiatus for two months, which doesn't strike me as being very likely since British TV doesn't really follow the same kinds of broadcast patterns that American TV does (if we were dealing with an American TV show, I could easily see them taking a two-month hiatus in the middle of broadcasting Series 14).