Joao was a great host, he gave us some excellent recommendations of places to eat nearby, we ended up at 3 of his suggestions and they did not disappoint! The flat is in a great location too, if you don't mind climbing the 4 flights of stairs.
There were only 2 downsides:
1. if there are residents in the flat above, the sound of walking around comes through the ceiling very loudly - I'd recommend using ear plugs when sleeping;
2. the shower fitting was broken on the weekend we visited, and the water wasn't particularly hot.
Other than that, we had a wonderful time in Lisbon, and Joao certainly helped make that possible! Thanks!