We didn't meet Sandra because we arrived late from the train station. She made sure keys were left with someone else at the apartment, and we were let in without much problem. Note that the apartment is actually to the right of the door labelled 31.

The studio was actually quite large and spacious. It was clean, and it had everything prepared. It was comfortable for both myself and my girlfriend. We only stayed one night, but wish we could have stayed more. Highly recommended!