Make the jelly fillings: gently warm the water in a small saucepan, then add the gelatine powder and stir until dissolved. Don’t let it come to a boil. Once dissolved, divide the mixture evenly between 2 small jugs. Flavour one with the caramel sauce, and one with the brown sauce. Stir until completely dissolved then pour into the smaller, 3.5 centimetre moulds, and put in the freezer for 1 hour.
Make the shells: put the orange candy melts into a mixing bowl set over simmering water. Once the water comes to the boil, switch off the heat and stir the candy melts until they’re melted. Spoon them into 12 of the larger, 7 centimetre moulds and use the back of a spoon to smooth the mix around so the shells are well coated. Put into the fridge for 30 minutes to set, then carefully turn them out. Repeat until you have used up most of the candy melts - save 2 tablespoons in the bowl for sticking the shells together later.
Make the stalks: melt the green candy melts and place into a piping bag with a very small hole cut in the end. Line a tray or plate with baking paper. Pipe 5 millimetre circles onto the paper then keep piping smaller loops to build some height until they resemble mini pumpkin stalks, then leave in the fridge to set.
Assemble the pumpkins: whip the cream and icing sugar to firm peaks then put it into a piping bag with a small hole in the end. Remove the set jelly fillings from their moulds. Half fill each shell with cream, then insert a jelly middle into each one. Put them into the freezer for 1 hour.
Re-heat the remaining orange candy melts and put it into a piping bag. Melt the black candy melts and put into a piping bag with a very small hole snipped off the tip. Pair up matching halves of shells and stick them together using a small amount of melted orange chocolate around the rim. Use the black melted chocolate to pipe a pumpkin face onto the front, then more orange to stick the stalk on top. Leave to rest in the fridge for 30 minutes before serving.