Tomek's description of how to find the flat was very accurate and we found it with no problem. We took the recommended route from the airport by taxi but we paid 25€. On the way back to the airport we traveled by metro and it was fine.
We met Tomek's friend Ricardo and he showed us everything
The location of the flat couldn't be any better-everything is at the door step.
The flat was well equipped and there is everything you need, including fast wifi and the UK plugs in the sitting room were a bonus.
We found the electric in the kitchen a bit dodgy- some of the sockets were loose and the kettle+cooker will trip the circuit breaker.
I would definitely go back and will recommend to my friends.