azdak

Does it manage to de-Tiffany itself because the Baron is faux!Hungarian, and therefore it gets a pass as exotic? I suspect the London-based producers won't notice in any case, and if someone does they can lampshade in production as legionseagle suggests.

It crops up in Sayers, in that Harriet at some point or other addresses the Dowager Duchess of Denver as "Duchess" (found it, penultimate chapter "Bunter never said that, Duchess!" A line with so much potential out of context!), and in that context it clearly indicates a much greater connection/intimacy than "my lady" would, more like the equivalent of calling your mother-in-law Mrs Wimsey.

I've got to say, while I couldn't even try Bridgerton because I knew it would annoy me, I feel I could manage the Central European version!