Mix the cream and milk together and pour 200ml into a small saucepan. Break up 75g of Dark Chocolate into pieces and add to the saucepan. Heat gently, stirring occasionally, until hot and thoroughly melted.
Meanwhile, pour 200ml cold water into a bowl and stir in the Vege-Gel. Transfer to a small saucepan and heat through, stirring, until just about boiling.
Quickly stir one-third of the Vege-Gel liquid into the hot chocolate milk and mix well. Divide the mixture between 6 x 200ml heatproof glass dishes. Leave aside to cool. The mixture will set quickly as it cools.
Pour another 200ml cream and milk mixture into a small saucepan. Break up the Milk Chocolate into pieces and add to the saucepan. Heat gently, stirring occasionally, until hot and thoroughly melted.
Stir in half of the remaining Vege-Gel liquid until well blended. Divide between the 6 glasses and cool as before.
Repeat the heating and melting using the remaining cream and milk mixture with the White Chocolate. Add the Madagascan Vanilla Extract and the remaining liquid Vege-Gel, reheating to melt as necessary. Pour into the 6 glasses and leave to cool.
Chill the desserts for at least 2 hours before serving. Sprinkle with grated Dark Chocolate to decorate.