Dad's London

My Dad was born in East London during the war. In the early sixties he joined the merchant navy and travelled to South America. He has done may different things, but he has some very funny ideas.
Even though he has travelled to the other side of the world the fact that I work in South London freaks him out. He doesn't like crossing the river. I've always known that about him. What did surprise me today was when he announced that people from East London are taller than people from North London. He reckons it is because there is more of a cultural mix in East London than North London (is that even true?). I must ask him about his thoughts on West London....