By Laura McGuire Chain restaurant Tortilla Mexican Grill said it will “double down” on franchising to help capitalise on growth opportunities in both the UK and internationally. It forms part of a five part plan unveiled by the business to help drive profits over the coming years. The casual dining chain said on Wednesday revenues grew 14 per cent to £65.7m in the year to December. Adjusted EBITDA also saw a 16 per cent year-on-year increase to £4.6m, while its loyalty scheme saw a 116 per cent uplift in users. During the year, the publicly listed firm opened six sites and one franchise store …