I found these photos while looking for references of Victorian back-alleys and slums. I think these are good examples of how cramped and make-shift the housing was during the time. With massive influx of the people moving into the London during the 1800, the population increased from a one million to just over six million within an century.

From these photos I can see several elements which I could use for our environment. The different shape and styles of windows give the buildings there own uniqueness. I think the top image would help with the development of the roofs, as its looks like its been pieced together like a jigsaw.