Preheat oven to 180ºC. Combine flour, sugar, chocolate, milk, cocoa, and butter in a bowl. Mix until smooth. Spread into an oven proof Pyrex dish.
Make shallow holes in the top and fill with caramel treat (about 1 Tbs). Use a spatula to spread the top of the batter to cover caramel.
Make the sauce by mixing the water, cocoa and Muscavado sugar in a heatproof jug. Using the back of a large metal spoon, pour the sauce over the batter.
Bake for 35-40 mins, until the top of the pudding is just set. Let stand for 5 mins before serving.
Serve with fresh seasonal fruit (fresh orange segments).