Not so sure about Orihuela Costa as I don't tend to go there at night. However, there are many fine restaurants and bars in Torrevieja which are used by Spanish and some are a delight. I just wish I could remember the names but I'm useless at that. There are several fine Tapas bars in Torrevieja which are very reasonably priced. I have found a couple of really good Spanish bars where speaking Spanish is very much appreciated. A marvellous Spanish Italian (does that make sense?) away from the seafront and they are all very competitively priced.
One thing I have found, us Northern Europeans do tend to eat far too early for the Spanish. For us, 8 o'clock is usually the time for our restaurant meal and the places are usually full of us lot at that time. Come 10 or 11 at night, the same places are heaving with the Spanish. Because of the working hours, they tend to finish late, stop off for a coffee and small beer or brandy on the way home and then relax for a while before going out for the evening. This was brought home to me a few years ago when we were staying at hotel in the centre of town. We'd eaten, been to a very nice (quiet) bar and noticed that many of the bars were closed. On the way back at about 11:30 pm, the same bars which were closed at 8 were now open and filling up nicely.
Where I live (Blue Hils) it is mainly expats (Northern European type) and the restaurants and bars are geared towards our timing. The restaurants have usually done their main business by 10 or 10:30 and the bars wind down around midnight, Torrevieja, on the other hand, is lively and leaping at that time. Even the funfair, where I take the grandkids to on a Saturday night, is mainly full of us lot in the evening whilst very young Spanish kids are still going strong at 11 or even midnight when our little uns are safely tucked up in beddy byes.
We do have several good restaurants in El Galan but they are mainly Brit orientated. Even the tapas are more like antipasto or hors d'ouevres as they are served as a starter. There is one excellent Spanish restaurant (cant remember the name) which is very reasonable and the rack of lamb is superb (€34 for two including starter, dessert and wine) plus live dancing on Saturdays in the summer (in the outside garden). Unfortunately, the demand appears more for the fish n chips and Sunday roasts and this is what is provided in the majority of restaurants. (Avoid the Priory, microwaved pizzas and processed meat patties).