We really enjoyed our time in Porto, staying in the Mercure Hotel on the Praça da Batalha. It's fair to say that Laura and I got the best deal here. Our spacious penthouse room had a stunning view across the city. Peter and Rachel's was slightly more cramped and overlooked the air-conditioning units of the next building.
We held a short geocaching event in the square outside the hotel on our first evening (Meet the Reluctant Brexiteers) and met a couple of locals: "While you're in Porto, you must go to Café Santiago on Rua de Passos Manuel and try the francesinha". So we did. Reaction was mixed.