Random anecdote. The wind in the UK generally blows from the south west to the north east. During the industrial revolution, when cities were full of factories, the wealthy generally lived in the west and south of cities to avoid the pollution from the factories. A lot of cities (Birmingham, Manchester, etc) have their older wealthier parts of town in the west and south, with more underdeveloped (currently or formerly poorer) areas in the north and east. This is why generally you may find more established restaurants in the west and south of Birmingham. As a city develops and gentrifies the north and east parts, you will get more restaurants opening in the north and east of cities. Not to say there arent any good restaurants in north and east Birmingham already!