Wouldn't you want an area with both? I may be missing the context of London's culture - but if 'up and coming' means 'being gentrified' wouldn't you want to pick an area that has a barbell distribution of upper class and lower class establishments?
Worst: some areas are very coffee-dense only because they're close to large transportation hubs, which usually don't make for great areas. Chicken shops gravitate towards entertainment areas, which may or may not be "up and coming".
