Blackmarsh: the Aviary Street Plan
I used to live in central London, close to Primrose Hill, while studying at university for my undergraduate degree. A lot of the fancier streets in the city have communal gardens in the centre of squares. I would walk by at least one most days, reading their polite notices stating that 'the gardens were for residents only'. The Aviary is partly based off these areas, with its air of exclusivity and the high walls hiding who knows what.
There are no shops in this borough because the wealthy citizens of Blackmarsh don't go out shopping - boutique owners, perfume masters, hairdressers, foreign merchants, and anyone else dealing in exclusive and expensive wares come to directly to them.
"The Aviary: Where the rich preen their feathers and plot against neighbours."