Put the granulated sugar in a saucepan with the measured water and heat gently to dissolve the sugar. Increase the heat, bring to the boil and stop stirring. Boil for 5 minutes. Remove from the heat and allow to cool.
Set aside 2 tablespoons of diced fruit, and put the remainder in a food processor or blender with the cooled sugar syrup. Blend until smooth. Add the lime rind and juice to the purée and pour into a shallow metal container. Freeze for 3 hours.
Remove from the freezer and beat with a fork to break up the ice crystals. Stir in the reserved diced fruit, return to the freezer and freeze until solid.
When ready to serve, remove the sorbet from the freezer and allow to stand for 10 minutes. Scoop into small glasses and serve topped with a lime wedge.