It would have been a perfect stay if it wasn't for the inflexible treatment they reserve me at the end.
I left the keys inside the flat for my check-out as I commonly do after an Airbnb stay and they fine me 50 pounds (that became 25 pounds after complaining) because I didn't follow the check-out instructions that were sent to me the very first day of my stay.
Airbnb aims to enable travelers to “feel at home anywhere you go in the world”, in this case I felt the strict and uncompromising treatment of having to deal with an agency.