It was three of us who needed to stay at Mario's place. The flat itself was spacious and good enough for 3/4 people. So two couples would fit there without an issue. The main issue was that we didn't have two sets of keys. This is very inconvenient. Also, the kid upstairs runs up and down at 7 in the morning which is not ideal.
It was a standard flat in London which is great for 1-3 nights. Thanks for the quick communication, that was great.