1. Place a trivet in the base of the slow cooker cooking dish. Pour around 1" (2.5cm) of cold water and switch the slow cooker to high. Lightly sprinkle four individual pudding basins with a little muscovado sugar. Place a few orange segments in each basin, followed by a spoonful of the cranberries. 2. Cream the remaining muscovado sugar with the butter until light and fluffy. Gradually add the eggs, a little bit at a time and a tablespoon of flour after each addition. 3. Sift the remaining flour, cocoa powder and baking powder together, and then stir it into the creamed mixture with the remaining cranberries. Add 1 tablespoon of cooled boiled water to give a soft dropping consistency. 4. Spoon the mixture into the basins. Cover each pudding with a double sheet of tin foil with a pleat in the centre to allow for expansion and secure tightly with string or by scrunching the tin foil around the rims of the basins. Place in the cooking dish and pour around sufficient boiling water to come halfway up the sides of the basins. 5. Cover with the lid and cook for 3 to 4 hours, until firm to the touch. Carefully remove the puddings from the dish and leave to rest for 5 to 10 minutes before running a knife around the pudding edges and turning out on to individual plates. 6. To prepare the chocolate sauce, melt the butter and chocolate in a heatproof bowl set over a saucepan of gently simmering water. Add the extra sugar and golden syrup, and stir until dissolved. 7. Next, stir in the milk and continue to cook. Stir often until the sauce thickens. Serve with the puddings.