We had a lovely time at Goncalo's flat!
Located very conveniently near both Metro and Bus stops and in the thick of Alfama, which was great for exploring on foot.
Goncalo warmly greeted us with Pastis de nata (custard tarts, you will love them!) and a wealth of useful local tips, which we took him up on. There are loads of cool cafes/bars very close by. Ask him for Fado (traditional music performed live) recommendations.
Would highly recommend staying here. There is no rooftop as I originally thought, it's views from one of the flats windows, which overlooks rooftop and, provided no cruise liner has docked, pleasant river views.