I stayed here with my spouse, two grown siblings, and parents (late 60s). We had plenty of space for everyone and the apartment was very clean and overall well kept. Very close to Kings Cross station (2 min walk) and easy to get around London. The check-in instructions were clear and the flat was easy to find.
The apartment is a little bare-bones though. There weren't top sheets for the beds (just quits), and the upstairs couch didn't have a set of sheets. It would have been nice to have a coffee pot and microwave so we could have made breakfast. Buying breakfast every day for 6 got expensive, and that's one of the reasons we wanted to stay in an AirBnB.
I would stay here again, but recommended the above changes to the host.