I have experience in what you describe, as I live far from London in a place I'm not from. Yes it can be very insular and can take many years to even begin being treated like a local (it's not until you have a kid, so I'm told).

I'm treated with suspicion too. A lot of it is 'not from here [the village/town/county]' (and not sounding like you're from here) rather than 'not white' or 'not from the UK' so I can't hard agree it's strictly xenophobia/racism etc.

And your anecdote about that guy: exactly what I'm saying. Everyone out for themselves. Selfish. Unrelated to racism or xenophobia etc

But are you saying in London everyone falls over themselves to hold open doors, let you skip queues, always waits for people to get off the train first, nobody barges past anyone, every single shop worker says "hello good morning" "thank you" "have a great day"...? What acts of making you feel welcome exist in London that doesn't elsewhere in the country?

edit: And you started "I agree...but not with the unfriendliness" then ended with "London can be unfriendly" so I'm a bit confused :D

I don't have any identical comparisons of politeness in London and the rest of the UK, but subjectively I do feel people in London are more likely to hold doors, let me skip queues, etc. There's just more of a feeling that we're all trying to navigate life in the city together, rather than gatekeeping each other's presence in it.

It's even more noticeable with people who are paid to be polite: bar and waiting staff, the folks working at Tesco, pub security, the kebab man. I walk into a pub in the middle of nowhere in England, they treat me like I'm intruding or inconveniencing them. I do that in London, they just ask "What are you having love?".

There is definitely a lot of veiled and outright racism and xenophobia though. I've heard things like "your English is actually pretty good" (I was a BBC journalist, it's better than theirs), "at least you're not on benefits", "at least your people are not as bad as X". I've never been told these things in London.