> In Britain, people from both places will leave their shoes on indoors at home

This is by no means a universal thing here!

I was stereotyping a bit for the sake of brevity.

And yes, even the queen is not universally accepted. Famously, the Labour party used to be republican, but seems to have mostly given up on that plank of policy.

In any case, my main point was that intense local rivalries exist, but actual differences between neighbouring places are typically fairly minor.