LOCATION:
Mercedes and Enriques place is very well located. The main train station (Atocha renfe) is some 3-4 minutes walk from her place. The museum mile, or Passeo del Prado, where all the major museums are located (Reina Sofia, Prado, Retiro Park, Thyssen-Bornemisza...) is also within walking distance from the apartment.
In the streets around there are plenty of cafeterias and small shops.

APARTMENT:
The apartment itself is very nice and cozy. It's on the 4th floor (no elevator) and fits maximum of 4 people.
It has two small bedrooms (one with bunk bed) and a nice dining/living room with windows looking out to the street and a magnificent treetops. We missed windows in the bedrooms though.
It can get a bit noisy, but if you close the windows the noise is almost completely gone.

HOSTS:
We unfortunately did not get to meet Enrique, but were greeted by señora Mercedes and here granddaughter. They showed us around the apartment and gave us some insider tips for typically Madridean tapas bars.

All in all, it's a very nice place to stay at! We enjoyed our stay here.