We had a great time at the flat, it was in a perfect location from the airport which made getting to our flights effortless. :D
The wooden style of the flat was really nice. What would be nice would be an HDMI cable or Chromecast so you could connect your laptop to the TV and watch Netflix on there. So if you plan on doing this, you should bring a cable or Chromecast. But that would just be the cherry on top.
All in all it was a very nice stay in Madrid and the nearby store should be mentioned in your description as it is just 3 minutes away and a huge plus for your flat.