Everything good. The flat is easy to reach and access thanks to the indications provided.
It is a good place to stay for a night. You couldn't be closer to Atocha station and the underground.
There are windows on the street but it isn't too noisy. Just be careful if you like to sleep in the dark you should take a sleeping mask because there are no shutters, just a blind on the window.
I would definitely come back on another trip to Madrid.