Put the dried cherries, raisins, sultanas and cherry brandy in a large mixing bowl (not a metal one) mix well and cover, leave to soak overnight at room temperature.
The next day, preheat your oven to 150°C/130°C fan/gas mark 2. Grease and line base and sides of a 20.5cm (8in) round loose-bottom cake tin with baking parchment or 2 small 10cm (4in) tins. Wrap a double layer of newspaper or brown paper, 3cm (1¼in) higher than the cake tin, around the outside of the tin and secure with string. This prevents the cake from drying and the fruit over-cooking.
In a food processor whiz the drained black cherries and set aside. In a large bowl, whisk the butter and sugar with a handheld electric whisk until light and fluffy. Add the eggs one at a time, beating well after each addition. Gently fold in the cornflour, mixed spice and polenta, followed by the ground almonds and chocolate.
Finally stir in the soaked fruit, glacé cherries, cherry purée and 4 tablespoons of the reserved syrup. Tip into the prepared tin/tins and smooth the surface. Bake for 3¼ hours, or 1½ hours for smaller cakes, or until a skewer inserted into the centre comes out clean. Set cake tin on a wire rack, cover with a clean tea towel and leave to cool completely.
When cool, remove cake from tin (keep it in its parchment paper) and wrap in a couple of layers of clingfilm. Store in a cool, dark place for up to 3 months.
FOR CANDIED ORANGES:
Make a syrup by putting 200g caster sugar with 150ml water, bring to the boil and simmer for 5 minutes. Cut an orange from top to bottom in half and cut each half into thickish slices. Add to the syrup and gently simmer for 5 minutes. Remove the slices and place on a parchment lined baking sheet. Bake at 130°C/110°C fan/gas mark 1 and cook for 30-40 minutes until the oranges dry and harden slightly. Cool and use to decorate your cake.