Begin by whisking the 6 oz (175 g) sugar, eggs and oil together in a bowl using an electric hand whisk for 2-3 minutes.Then sift together the flour, bicarbonate of soda and the mixed spice into the bowl, tipping in all the bits of bran that are left in the sieve. Now stir all this together, then fold in the orange zest, carrots and sultanas. After that pour the mixture into the prepared tin and bake on the centre shelf of the oven for 35-40 minutes, until it is well risen and feels firm and springy to the touch when lightly pressed in the centre.While the cake is cooking, make the topping by mixing all the ingredients in a bowl until light and fluffy, then cover with clingfilm and chill for 1-2 hours or until needed. Now you need to make the syrup glaze, and to do this whisk together the fruit juices and sugar in a bowl.Then, when the cake comes out of the oven, stab it all over with a skewer and quickly spoon the syrup over as evenly as possible. Now leave the cake on one side to cool in the tin, during which time the syrup will be absorbed. Then, when the cake is completely cold, remove it from the tin, spread the topping over, cut it into 12 squares and dust with a little more cinnamon.