The flat was clean, the location is good, in walking distance to Buckingham Palace, Hyde Parc.... Very convenient public transport (direct line to St. Pancras and Victoria). Lucka replies quickly (though we missed a personal contact).
These are the positive points.
Now the negative ones:
I didn't see on the pictures that the flat was in such poor conditions, shabby furniture, crack in one window, electric cables not fixed, no decoration at all, a total lack of cosiness.
I've been using airbnb for years and I've had always good experiences. This is the first time that I am so disappointed. What a pity!