The landlord speaks Spanish and probably basque, only little French and almost no English. Nevertheless, they used some translation tool and replied to emails and WhatsApps really fast and the communication worked quite well.
Due to traffic we were late for passing on the keys but they were very uncomplicated, as was the introduction to the flat.
The flat is situated between the main beach and the central streets. All surf schools and shops are close by as well as many restaurants. (When we were there, there was a basque festival. The concerts and parties are just down the street, so when hendaye celebrates, it is not exactly quite.)
The flat itself is as described, well equipped and clean. Only thing missing is something for sandy and wet shoes right at the entrance.
For everything else there is not much to say but very good.
If going in that region again, which is very nice by the way, I would definitely book it again.