A typical British housing estate is "mass produced" but it isn't built on a production line. Also they're not built with anything like the tolerances and quality control you'd get on a production line (e.g. it's a hot/cold/wet day and the bricklayer just wants to get finished as soon as they can).
The only sector in British housing building that is making serious use of production line techniques is the social housing sector, where often timber frame structures are used. These timber frame "modules" are manufactured in a factory and so can easily go through the QC processes you'd find on a production line before being shipped-out to the housing estate.