The restaurant was less than one quarter full when I was rudely turned back by the waitresses, claiming that they were fully booked (I believe, from my small understanding of Spanish, after listening to their conversation, that it was because I only speak English).
I continued happily on my way and had a delightful meal, with outstanding service, at Alter Zeppelin down the road.
On my way back I popped in to see them, and amazingly the restaurant was still only half full!
My advice? Don't bother! There are plenty of other lovely places to eat, with staff who genuinely want to make sure that you have a good experience.