We had a wonderful 4 nights at Maria's apartment. It is beautifully designed and a very calm place to retreat to after a day a sightseeing in Madrid. It's perfectly located, in close proximity to the Opera House and the Royal Palace. We walked everywhere.
Maria met us with the keys, a map and 3 different itineraries - which we followed - and had a wonderful time!
The little touches, like milk and juice in the fridge, the coffee machine, herbal teas and mini muffins were a treat; as well as the practical things like a European adapter plug.
Maria messaged us a few days in to check we were okay and even told us of a luggage storage unit we could use as we had a late flight (€8 per bag).
I would highly recommend staying here- and following Maria's advice to go to a flamenco show!