I too am london born and bred, but this is an interesting topic.
London is one of the most culturally diverse cities in the world, many people from across the globe will testify to that and i certainly have made the most of what london has to offer culturally.
Sometimes things can be on your doorstep but we just take it for granted.
My grandparents are St Lucian, my parents were born and bred here and I consider myself to be simply black british.
My partner is Lithuanian born and bred, he's been here for 4 years.
We are expecting our first any day now, 5 days late!!!
I am a fairly well travelled person but I honestly havent seen more of a mix of people anywhere else than walking along a London street!
Having said all that clearly its not the same as a first hand experience of being in another country and 'feeling' the culture, soaking it in and appreciating - or not - the differences.