Jon's flat is situated in a very calm neighbourhood in the London Borough of Hackney. When going to the city centre, you can either take a bus (just over the corner) to London Euston or take the Overground train to Liverpool Street and then take tube.
I travelled with my family and Eric, Jon's friend greeted us on the day of our arrival and explained everything about the flat.
Even though we stayed during the festive time (We were there for New Year's Eve), the apartment was calm and quiet. It is situated on the last floor of the building (no worries, there is a lift), so you don't hear the neighbours.
Thanks, Jon&Eric!