It was really a bit like being in a museum, we all felt very comfortable. Remarkable how so many statues can be kept clean and dust-free :-) The beds were good, the kitchen fully functional and very well equipped.
Quick responses and reactions from Federico: A sticking balcony door e.g. was fixed the same day, thank you.
The roof terrace was only not too hot in the mornings and at night, but the view was great.
Top marks all around, we would book the apartment again.