Autumn Vine's flat was our home base for our ( my wife and I) 6 day Madrid stay. Great location. 2 minutes off of the Gran Via ( 5 minute walk to multiple Metro Lines), easy access to hundreds of restaurants as well as numerous tourist spots you are going to want to visit.
Check in was super easy with great " pictorial" directions. You are smack in the middle of central Madrid so don't expect a huge flat. It was perfect for a couple. Spotless, bright and surprisingly quiet.