The host was just lovely, he was very flexible regarding check-in and check-out times.
I've heard from other people that Balat isn't really a safe part of Istanbul especially during the night, but our location was right by the coast and had really good public transport right at our feet - so we never had to worry about it!
Our first night was a bit scary though - random people just showed up at 2 am blasting the doorbell and again at 5 am. We couldn't reach Mehmet and had to wait the night out. We did have a talk the following afternoon (he suspected it was previous guests who needed a place to stay) and from there on it was smooth sailing. He even brought over some cheesecake and offered some pastries which was quite nice of him!
The space itself was even better than I expected, the photos need to be updated haha!
All in all it was a really good deal and a really great host, would definitely choose this spot again :)