I usually go to bed between 9.30 and 10 but read until 10.30 ish. DH can sometimes stay up later than me but we can't break the habit of waking up at 5.45 am whether we set the clock or not. One or other of us makes tea and we watch the new, catch up on our phones and drink tea for an hour or so.
DH can nap during the day but I find it impossible.
To think that London, or anywhere else for that matter, does not belong to any one demographic