The apartment was excellent and exactly as described, and Herve was on call and in touch throughout. I'd highly recommend it.
The location was fantastic, close to everything yet down a private side path. Beach 30 metres away, restaurants right there, bars on hand and food market and bakeries etc 3-5 min walk. As good as it gets in Biarritz. Wifi quick, bed very comfortable (and we are high maintenance). Great shower. Needs de-humidifier on - and fine then. Felt very safe and secure as well.
My only observation: if you like to sleep with the window open - you can hear some noise from people coming and going from the local bars. Cannot hear at all with the windows closed.