I can recommend a very good restaurant in San Javier called Vintage La Barra.
It's a proper Spanish restaurant that does Tapas as well as having an a la Carte menu (which has a fixed price option).
Food is delicious and the staff are very friendly.
It's on Avenida a la Union (head into San Javier & turn right at the petrol station...it's along that road on the right)
It's definitely worth a visit. If anyone else can recommend a local restaurant, let me know!