Overall, it was a great stay. Anabela is a great host, she's very friendly, communicative and open. She responses quickly as well. The place itself is tiny, but would easily fit 1-2 persons and it has everything you might need in a short trip - a good bed, modern and clean bathroom, nice and decently equipped kitchen. There is no air conditioner, but it wasn't too bad during my stay in regards of the heat. Nevertheless, she provided me a fan for that. The location is great as well, right in the heart of Madrid center. In terms of the sleep quality, if you're an early bird and like to go to sleep early it could be difficult - the windows are to the internal part of the building and neighbours are pretty loud. You can hear tv noises and things like that till around 1am. It wasn't too bad for me though, just FYI.
The only issue I had is a construction workers inside of my room mounting a bed upstairs, who occupied the apartment for half a day basically with no option for me to stay in. I believe ideally for such a thing the apartment should not be occupied by a visitor during that day. But Anabela let me check out a couple of hours later the next day, so this justify the inconvenience for me personally.
I would definitely stay there again and recommend Anabela's apartment to anyone! 👍