Cover a large, flat baking tray with foil. Place small scoops of vanilla ice-cream on the tray and freeze until hard.
Melt chocolates in separate bowls over pans of simmering water. Once melted, set aside to cool.
Transfer ice-cream scoops to a wire rack over a baking tray and spoon the dark chocolate over each scoop; it should harden immediately.
Garnish each with a little of the milk chocolate. Freeze until firm before serving.