I find it shocking that someone thought it was a good idea to list a flat on airbnb that they're only renting themselves. Largely in England subletting is not allowed under the terms of rental agreements.
Yeah, that's one thing I wasn't clear on from the story, whether or not the host was violating the terms of his lease.
It's not just in England. In the US, while subleasing is sometimes allowed it is almost always forbidden for short-term rentals. Many landlords now include explicit "no AirBnB renters" clauses in leases as AirBnB has become more popular.