We stayed 5 nights with 5 people in this lovely flat and would highly recommend it. It's very good location close to city center and to the Douro (river). It's very clean, well equipped, nearly feels like home. We had a very friendly welcoming and always a number to call if needed of information.
Thanks to this flat we could visit the all city easily and get some rest when back to it. If you don't feel like going too far, on the same street there is restaurant, little shop and café.
We had a lovely family holidays. Thank you Joao for your advice always good and quick response.