We ended up leaving the apartment a day early and checked into a hotel because the main bedroom bed was so uncomfortable that we couldn't sleep through the night, and spent the second night on the floor. (One of our party had accessibility issues and could not use the bed up the mezzanine ladder.)
Martyn has a lot of automated messages that come through which leads to a professional appearing hosting service, but did not see my message about the bed the morning after our first night, and could not get himself or anyone else to come and look at the mattress to understand the problem, meaning nothing was done to address our discomfort.
Very disappointed. Sadly my entire experience of this stay means I am no longer using airbnb, and am going back to hotels.