To make it short: I really recommend this place, even if you are in Lisbon for several weeks as I was.
This place has AC, a well eqipped kitchen, all basics (herbs, soap, detergent etc.), a comfy double bed, is in the middle of Bairro Alto and many nice places for coffee and food are just around the corner.
During my stay, it was really quiet and peaceful in the neighbourhood.
Communication with Brigida was always easy and responds came quickly. This and the flat itself made me extending my stay without hesitations.