The UK is always complicated....
There isn't another country that I can think of in the same situation. It's a geo-political entity classed as a country but which consists of several individual countries. You could compare it to the USA and the individual states, but that's at a lower level. Or a continent and the individual countries, but that's at a higher level. Or a country and its counties, or laender, or whatever. But whatever the level and subdivisions, there will always be cultural differences between them.
You used France and Paris as an example, but I could show you USA and then try to say that it's impossible to represent everything so we have to use Tom Sawyer as a representation of someone who is quintessentially American. Or what other fictional, stereotyped characters are there that non-Americans think of first when they think of America? And why on earth could anyone think that a rat is quintessentially French.
The problem is the IP...
In China, Canada and France, we have attractions that do actually demonstrate how diverse these countries are (and I'm not talking about the Beauty & the Beast Sing-Along). In Norway, we used to have an attraction that explored the folklore of the country and another one that also showed the diversity of the country. All of the country pavilions pick some sort of typical architecture or famous landmark and the Germany pavilion was meant to have a Rhine river cruise, not trying to claim that these are what's found everywhere in those countries but a few examples. It should not be difficult to fairly represent the country and its people as a whole, without resorting to stereotyped fictional characters.
The Amercan Adventure successfully gives us the entire history of the USA in 25 minutes!
The UK pavilion could be expanded with atttractions that focus on each country, history and folklore, environment, language....or one attraction that does them all, to demonstrate that it's a diverse nation. It could be a film like some of the others, or an omnimover, or boat ride. But of course present-day Disney is not going to do that. I'm sure there are people who don't even realise that the UK consists of four countries, I regularly hear people talking about the English pavilion. And I came across someone a couple of months ago who thought that Welsh was a regional dialect of English. It doesn't help to keep re-enforcing those misperceptions by rehashing the same stereotypes.