Gurhan's apartment is the perfect base for exploring Istanbul. It's a 5min walk to Istiklal street (major shopping street), and maybe 15-20min walk down to the "centre" of Istanbul near down from Galata Tower / near the water. Gurhan was extremely communicative before the trip, and provided very in depth instructions of the self-check in process.
The flat is lovely and feels spacious for a small flat. It's been kitted out very well with a kitchen which is basic but with all that you need (including a fridge and washing machine), a big bathroom with a hot, powerful shower, and the double bed on the mezzanine level (which did not feel claustrophobic at all, as some mezzanines can). We visited in January therefore did not use the balcony as much as we may have done in summer, but it was a nice addition to the flat, with beautiful views over Istanbul. All in all, would really recommend Gurhan's place as a comfortable base which is very good value for money!