"99% of my knowledge of british culture comes from Doctor Who or Top Gear" Unfortunately, this is probably true for too many people, amirite?

I mostly agree with you but I learned some British slang from reading Harry Potter lol

What does Harry Potter show? London. And some coastline. In comparison to those mentioned in the post Harry Potter offers very little insight into the British culture. Of cause, it may have something to do with the fact that I'm British myself.