Helena's apartment is a 15 minute walk from the centre in a typical Portuguese neighbourhood. There's a great bakery nearby for breakfast and two supermarkets about a 5 minute walk away. The metro is also about two minutes away. Helena responded to all our messages very quickly and had no problem with our late arrival due to our flights.
This flat is really good for two people but felt a little small for four of us. It's also not for light sleepers in the summer as the whole apartment building is rented to tourists and the ground floor flat's noise carries upwards - we unfortunately had a loud group of people downstairs who kept us awake.