Given that England itself used to be multiple countries (Wessex, Mercia etc all with their own kings) and that the majority of us are probably descended from Romans, Vikings & Gauls we could be here for months discussing internal racism if we wanted to get pedantic.
My friend has lived in Plumbstead for 10 years quite happily with no issues. Personally I'd rather liver on that side of London than the SW/Surrey borders areas, but then I'm half Cockney/half Eat Croydon so I guess I'm biased!
FWIW the doors aren't my thing, but I can see why people would like them. 