Has more to do with where the industrial centres of the 19th century were within a city and how cities have evolved and developed over time, making those centres prime residential zones now. In Bath's case there is a clear need for more housing in the centre with massive objections from residents to the development of greenfield sites on the outskirts of the city.

Sites like these are politically 'easy' to develop. From a urban landscape point of view, taking an industrial zone and re-classifying it as a residential zone has it's risks in that you drive out the ability for employment opportunities in the city. However, in Bath's case, the industrial sectors are now on the west side of the city towards Bristol.