Add lime wedges, lime juice, mint and sugar syrup to a highball glass. Muddle to release the ingredients’ flavour with a muddler or bar spoon. Fill two thirds of the glass with crushed ice. Add premium dark rum and then churn with a spoon to bring all ingredients to the surface. Pack with more ice and top with a splash of ginger beer. Top with a few dashes of Angostura Aromatic Bitters.