Balat is a very interesting area. Where the room is located is very conservative but fascinating with the maze of alley ways and lovely buildings.
As suggested, the taxi driver phoned Mustafa on approach and he met the taxi and guided it to the room. (not sure what would happen if Mustafa missed the call!)
The room itself is interestingly painted but very basic. As regular airbnb users we are getting tired of bed coverings that aren't big enough for the bed.
As with all places hosts should provide water for arriving guests (not the remains of a bottle from previous guests). Also, some local information should be available in each room.
Back to the area- down the hill from the room, around various twists and turns, is a wonderful street of cafes. It seems to be the new trendy area of Fatih.