Preheat oven to 300 degrees F (150 degrees C). Grease five 8x4-inch baking pans.
Combine brown sugar, coconut, flour, raisins, fruit peel, cherries, baking powder, mixed essence, and nutmeg in a large bowl using a large wooden spoon.
Combine margarine and shortening in a microwave-safe bowl; heat in microwave until melted, 30 seconds to 1 minute. Pour melted mixture into flour mixture, alternating with milk, until batter is just mixed. Add water, a teaspoon at a time, if more moisture is needed.
Pour batter into the prepared baking pans, smoothing the tops with the back of a wet spoon. Sprinkle white sugar over each loaf.
Bake in the preheated oven until a toothpick or skewer inserted in the middle comes out clean, about 1 hour. Cool in the pans for 5 minutes. Invert onto cooking racks.