Many thanks to Marco who was a great host. He arranged a taxi transfer for us from the airport and a friendly welcome party with the key and instructions, despite us arriving quite late.
The location is about the best I ever had in Rome, really central to most of the sights, with lots of great little restaurants and the worlds best ice cream shop (Gelateria del Teatro) around the corner.
The flat is really quirky and well laid out (once you made it up the stairs). We stayed with two children (5 & 9), who loved the flat too.
Being a stickler for cleanliness, but taking into account that we were in Italy, we were really impressed.
However if you are looking for a longer term stay and would like to cook yourself, this might not be the very best place as the kitchen has its limits.
Tip: Bring some ear plugs if you don't like the morning city and bird noises, however that's part of its charm.
Note: This would not be suitable for elderly people or families with young children (prams are a no-no). There is no door between the bedrooms.
All-in-all; thumbs up for Marco and his Ancient Penthouse flat!