There was very good communication between Gustavo and ourselves, so it all went very smoothly and Gustavo made us feel very welcome, with lots of advice about things to do.
The apartment had everything we could want/need and extras eg toiletries etc.
The apartment was ideally located, everything within walking distance...beaches, bars, the market and a fantastic deli (Gustavo's recommendation). The terrace was great with the sun most of the day.
We would definitely stay again if we return to San Sebastián.