All in all we had a great stay in istanbul. the meeting with Fatih was well organized. we called him and 5 minutes later he met us at the meeting point to bring us to the appartment. he was very kind and organized very quickly a third bed, since we didn't inform him properly about a third person. to be honest, the appartement/room is pretty small for 3 people, others would have said too small. But that was not a problem since we went out to visite the city all day long. The only thing to mention is the kittchen condition: there is a possibility to cook, BUT when there is just a pan, no other pots to cook noodels etc and only one of two hotplate is working, cooking isn't that fun. but since there is a lot of good food in the area it wasn't a problem!
all in all, thanks for the great journey!