Except for "Grand Bretagne," I like this map very much. Great to see Hungary getting some power. Is there a war or any backstory? That's something I often do for people. And what are "Lands of the Black Lotus?"
As well as expressing my admiration for a fine, clean map with some great colour schemes in play, I also feel a need to express curiosity: 'Empire of Grande Bretagne'? That curious name does beg for some backstory.
Well, no real background. But I had a vague thought that the POD was far back enough where the names Britain/Brittany came to be used almost interchangeably due to the two regions being dynastically linked or something. Maybe there were no Norman invasions and Britain stayed united under Wessex, eventually merging with Brittany. Then we could say that over time Brittany became the senior partner... Or something.