Christian and his sister Mercedes are excellent hosts. Very quick to respond to questions prior to arrival. Mercedes' husband Jose was there to show the apartment when we arrived around midnight. He left a complimentary bottle of water, orange juice and wine. All much appreciated if you arrive at night. For the next day there were very clear instructions on where to find supermarkets and other relevant locations (restaurants, tourist office).
The apartment has all the amenities one would need. Two nice bedrooms, one of which has a single bed that can be made into a double. The kitchen is completely equipped so you could make your own meals. The bathroom even has a washer and a drier. So one could even wash clothes if you want.
Location is perfect. Just a small 10 minute walk and you are at the Cathedral. Although the apartment building is in a small side street, there can be some noise at night.
Mercedes even organised the taxi for us for the return, checking to confirm it the night before even.
All in all, excellent stay, great hosts, would recommend it. And Valencia is an amazing city!