With regard to the earlier properties, it's worth remembering that 'planning permission' didn't exist in this country until the Town and Country Planning Act came into force in 1932. (Previous Town Planning Acts, such as those of 1909 and 1919, empowered local authorities to build social housing but they didn't place restrictions upon what private developers could build. See here for far more detail:
https://www.createstreets.com/the-long-history-of-british-land-use-regulation ). So the design of houses prior to that date was largely down to the whims of developers, rather than under the control of local authorities.