We had a marvellous stay at Tugces apartment. Its literally next to the Taksim square in a sidestreet in the last floor (without elevator). The apartment is very clean with a nice balcony and strong Wifi. Communication was perfect and fortunately we were allowed to check out a bit later. It can be a bit noisy in the evening as its close to some sort of a disco but nothing super annoying for us.
Thanks for a wonderful stay in your apartment and we d definitely stay again next time we visit the beautiful city of Istanbul :)