The 'penthouse' description fits as this is on the top (7th) floor of a building with an elevator and there's a great deck with views. So close to the train station when we arrived, and close to museums (Prado and Reina Sofia) and the Retiro (park), plus great cafes on the street right outside the front door.
Sergio met us upon arrival and his orientation was cordial and enthusiastic. "Thanks for the wine, juice and strawberries, Sergio, and thank you so much for fixing the small, unexpected electrical problem so quickly."
The flat is comfy and well-appointed and we used the kitchen for breakfasts and the rooftop when it cooled in the evenings. Our party was originally just us, a family of three, so the two bedrooms were perfect; when joined by a fourth friend on short notice he used the pull-out in the living room.
During a heat wave as we experienced do not expect the A/C to keep the whole place super cool, but enjoy the evenings and nearby bars with cooling.