Manuel's flat is located at Vila Nova de Gaia, on the Southern bank of Douro's river: keep this in mind if you want to move above all around the city center of Porto, as transports are not so smooth and frequent as we thought.
Though we never met Manuel, he's been very responsive and helpful since the beginning: clear instructions to get to his house, which was in order. Sandra welcomed us and gave us the keys.
On our last day we had some delay in checking out, dued to some issues in renting a car downtown. Manuel let us keep our backpacks at his place after the check-out time limit: it has been very helpful and comprehensive.