Very cute! In the Wiltshire village where our last house was located we had two neighbours that had even tinier houses than that - each house was around 300 sq ft max - we called them the hobbit houses
.
One was owned by a single guy, but the other was owned by a retired couple, the husband of which was such a large guy we always wondered how he fitted into the teensy bedroom and imagined him Alice in Wonderland style with extremities poking out through the windows! The layout was similar, although in both cases the shower room was on the ground floor and the kitchen was in a minuscule extension.
The couple had bought theirs in 2010 from a family with three DC - and it wasn't a weekend retreat/holiday home either - but I guess that historically (it was an 1850s build) it had accommodated even larger families......