Place the melons, white wine and lime juice into a blender and purée.
Pass through a sieve and chill until ready to use.
Whisk the vinegar and olive oil together and season well.
Toss the langoustines in the dressing with two tablespoons of shredded mint and place in the centre of the soup bowl.
Whip the cream lightly then fold in the mint and season with salt and black pepper.
Spoon the chilled soup around the edge and top with a quenelle of the mint cream.