Begin by making the sugar syrup. Add the water and caster sugar to a saucepan and bring to the boil, stirring occasionally. Set aside to cool while you make the mango puree.

Place the mango chunks in a blender and blitz until smooth. Add a splash of the sugar syrup to help it blend smoothly.
Place the pureed mango in a large bowl and whisk in the rest of the sugar syrup and the lime juice.

Transfer to a plastic box or other suitable container and place in the freezer, stirring every hour to break up the ice crystals. It should set in about 3 hours.

Garnish with chocolate Sauce.