I'll start.
Younger one has been Kevin the teenager since he was seven (now eleven). Talks in words of single syllables, though much prefers a grunt. Eats fast, with his mouth open. Laughs uproariously at older bruv's non funny jokes. Let's his gran hug him only when his birthday or Christmas is approaching.
Older one puts pics of himself and his best mate doing standing backflips that scare the shit out of his mum and his gran, on Instagram. Not funny.
To think that London, or anywhere else for that matter, does not belong to any one demographic
Adult early 30's - very difficult.