They are based on the houses I was brought up in, when they were built, they originally just had one window and a door downstairs at the rear, no rear windows upstairs. The lean- to kitchens were built on later, then for those that were lucky, a bathroom and toilet, hot water supplied from a small copper tank behind the coal fire, no water pump!
I also remember using the outside toilet (detail picture) no fun in the dark or in the winter. There was also a coal shed for each house, a ton of coal was delivered by lorry and tipped outside the back door, this was a real downer to come home after a full days work, knowing that it had to be carried in by hand!
Phil