Cafetería Arenal,
This conventional-looking bar-restaurant was a good tip from María for a slightly more upmarket fixed-price lunch menu than at Casa Parrondo and its neighbours. Being extremely early for lunch, we had the dining room to ourselves at first, which was weird, and the waiter to ourselves, which was nice.
The outward signs of the dearer menu (a whole €10 instead of €8 at Casa Parrondo) are the comfy chairs, table cloths, and proper wine glasses instead of beakers. That is all good, although the shinier decor is like a boring mid-range hotel's, and less cool than the other places' more homely charms. I keep expecting soft pink neon and some Julio Iglesias.