The flat worked very well as a base for exploring Santiago on foot-it's about a 15-minute walk to the cathedral (longer the first time until you learn the way!). Since it is in a large multi-story, multi-building complex, based on the address Google Maps got us reasonably close but there was nowhere we could easily stop to identify the specific building , and the underground parking for the flat would be impossible to find (or access) without help, so we were very fortunate that Bea, the owner's representative, maintained email and phone contact with us and enabled us to hook up. Especially for a larger vehicle, access to the parking garage and assigned spot is extremely challenging, requiring very careful maneuvering with assistance from our fellow travelers to avoid damage to the vehicle.
The flat is well-equipped, the beds are comfortable, the bathrooms/showers are good, the wi-fi works (in the living room but not the bedrooms). There is a third bedroom with a single bed that we did not need.
Bea made herself available throughout our stay for problem resolution (there were no problems).
Altogether a very good flat, especially with the additional support provided by Bea.
Restaurant recommendation: ComoVino in the old town is superb and reasonably priced; we went there 2 nights out of 3!