Diogo met us at the airport, which was lovely (and he refused to take money for the car park), and was proud to take us on a mini-tour of Lisbon. He gave us valuable advice about the city, and then took us to the apartment. It's clean, modern and very comfortable. It's quiet, on the third floor, and at the edge of the intriguing, somewhat rundown but historically and culturally engaging area known as the Alfama.
The steps up to the flat are quite steep but fine as long as you can manage about 40 stairs up and down.
Diogo made himself available via phone and email and booked our taxi back to the airport.
He's an excellent host, speaking very good English and possessing a sense of humour. He is highly recommended, as is his apartment.