I know El Campello well, as we used to live in Jijona, just inland from there.There used to be a bar there run by Brits called a womans name, for the life of me I can't remember it, something like Cassandras. She had a good following for Sunday roasts and was always busy but her mainstay was Spanish. You have the right idea in that you must cater for everyone. It is seasonal though , very quiet in the winter and heaving in the summer. It has a lovely prom and even in winter there can be alot of people walking up and down it.
Good luck