I would definitely recommend Nuno as a host. He met us at the Fado Museum and helped us to carry our bags from the car, gave us a small tour of Alfama on the way to the apartment, gave us great advice on what to visit and had a homemade bottle of wine waiting for us. He also came to the apartment a couple of times to replace a broken showerhead (which he fixed promptly) and to deliver a baby crib/cot and high chair (if you will need this, best to ask ahead of time).
It's worth mentioning that if you are renting a car, this place is not parking friendly as Alfama doesn't allow cars on its old streets, aside from trade vehicles, so it's a 10 min walk to where you can park your car overnight which costs 8 euros per 24 HR period. The apartment is also up quite a few stairs.
The apartment is in an excellent location though. It's just a few minutes walk to St George castle, the Lisbon cathedral, Miradouro das Portas Do Sol (one of the best viewpoints in the city), Rua Augusta arch, Pink Street and metro stops, where you can easily get to Belém.
There are also excellent restaurants nearby. We especially liked Patio 13, which had excellent meals all under 10 euros and is a 30-second walk from the apartment.
The apartment has some quirks, like if you use the cooker, you can't use much else electric without tripping the breaker, but those kinds of things are expected in an old building.
Overall, I'd highly recommend the place 🙂