Firstly, this place is VERY central, being about a 5 minute walk from Westminster Abbey, Houses of Parliament etc. I don't think it could be better located.
Amenity wise, there's a Tesco Express just around the corner, as well as a Pret, a Itsu, and a couple of nice looking restaurants.
The room is in a private house set in a secure courtyard. To get to it you either have to get buzzed in through the car park gates (don't know if car parking is included), or use a key to go through a hostel block.
The room was small, but clean. Bed was a basic single bed, clean sheets etc. There was a table lamp, and very importantly there was a plug right beside the bed.
Unfortunately there was no lock on the door. I don't mind this, but it may concern some people.
The bathroom was shared with others in the house. Plenty of toilet paper, but make sure you bring your own soap.
Finally, Frederico's mother was helpful, friendly and respectful. I'd definitely use this AirBnB again.