Flatshares are completely normal in many UK cities and they are marketed directly as Student Houses in places like Cambridge. Rightmove even has a special checkbox for them.
Flatshares are completely normal for students but those co-living spaces aim at people with several years of work experience who still can't afford their own flat in a reasonable location.
Strikes me that it's just a rebranding of flatshares for people who consider themselves too old and too professional to be living out a Peep Show esque post-university existence.