We were a group of 8 adults spending a long weekend in San Sebastian and we loved the villa! It's very spacious with amazing views from the bedrooms facing the front. We also enjoyed very much sitting in the garden/patio in the evenings for drinks. The location is great, the beach is just a couple minutes walk. We also enjoyed the stroll along the beach before and after going into the Old Town for pintxos. It's also only a short walk from the funicular. The villa itself was beautiful and clean, however being an old building, it's inevitable to have squeaky floors, staircases and doors.
Unfortunately, during the days we were in San Sebastian, the European rowing championship was taking place on the beach right in front of the house, so it was quite noisy during the day. There's also construction happening right next door although it was only noisy during week days. It shouldn't be a problem if you're planning to be up early and out during the day since evenings are still quiet.
The communication with Monica/Ane and the check-in/check-out were all very smooth. Overall we did enjoy our stay despite the external factors mentioned above.