Having stared at it until my eyes turned an unhealthy red, I think I've figured out the British quarter and buildings.
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The quarter itself is a more-or-less 1:1 recreation of the real-life Bank Junction—they even modelled the statue of the Duke of Wellington there! Other quarters usually do similar: they make a special-looking urban space that stands out but, notably, also fully includes the unique buildings in a particular way. It's like how the Greek UQ places the Parthenon up on a hill, with the Odeon down below. So, we have to figure which buildings stand out here in this completed quarter. Here's what I think:
The quarter itself is the
Bank Junction. It's fairly normal for unique quarters to recreate a particular physical space: Greece's aforementioned Acropolis is an imaginary replica of the Athenian Acropolis, and Mexico's Zócalo is a recreation of, well... the Zócalo city square of Mexico City.
The first building is the
Royal Exchange, the one with the glass inset in the roof and the tower behind. It's the exact same building and it stands out, so I don't see why it wouldn't be this one.
The second building is definitely not the Bank of England—that's nowhere to be seen in the quarter, not even a little representative slice of it. Instead, check out the dark brick and smoking chimney of the structure to the right of the Royal Exchange: I'm certain that's the key second piece here. I can't tell what it is exactly, but it looks like some kind of factory or maybe even an early power generation station (to match the Battersea wonder). Although there's already a Factory building in the game, it's not without precedent for unique buildings to kind of "double up" an existing standard one thematically or aesthetically: consider America's Railyard, which you could be forgiven for mixing up with the typical Rail Station.
Anyway, that's my reasonable speculation. My wild guessing is that they'll have some science-focused gameplay (look at how many rocket launch pads there are in the teaser screenshot!) and perhaps an aircraft unique unit. I'm also leaning on the side of them having a special "Great Innovator" sort of blanket Great Person, so we might see Isambard Kingdom Brunel as well as Charles Babbage—the latter a super neat fit with Ada Lovelace, I'd think.