I stayed a few days at Aranzazu's place where I had a fantastic stay. Great loft and amazing host. Very close to Madrid centre by metro (nearest tube station is 5min by walking) but in a very quiet part of the city at the same time. The loft is brand new, very clean, spacious, fully equipped and fantastic support & tips from the host (Aranzazu speaks English fluently which was really helpful!). I couldn't recommend it enough!