The problem with cafes and restaurants on airfields is business is largely dependent on good weather unless there is sufficient clientele from local towns and businesses.
Sadly, that is very true, and not only in UK. No cafe/restaurant can offer a decent level of service based only on local aviation custom. The saddest illustration is the resto at LFAC Calais, doing fairly well in summer, going bust in autumn, restarted by a new enthusiast in spring, only to repeat the cycle.