1. Put the raisins and sultanas into a bowl and cover with half of the orange liqueur. Cover the bowl and set aside for 24 hours.
2. When ready to bake, preheat the oven to 150°C. Grease a 20 cm springform cake tin and double line it.
3. In a large bowl, cream together the butter and sugars using an electric hand mix, until the mixture is light, pale and fluffy. Add the eggs one at a time, continuing to whisk. If the mixture looks like it is going to split, add a small amount of the measured flour.
4. Put the chocolate pieces in a heatproof bowl that fits over a pan of gently simmering water (the base must not touch the water), and stir until it melts.
5. Leave to cool slightly. Add the cooled melted chocolate to the egg mixture. Sift in the flour, mixed spice, cinnamon and nutmeg and fold in so everything is well combined. Then add the lemon juice and remaining measured orange liqueur and mix together. Finally, mix in the soaked raisins, sultanas, mixed peel, cherries, walnuts and hazelnuts.
6. Spoon the mix into the prepared tin. Level the surface and cover the top loosely with a piece of baking paper. Bake in the preheated oven for 2-2 1/2 hours, depending on your oven. Test to see whether the cake is cooked by inserting a thin metal skewer into the middle; if it comes out clean the cake is done.
7. Cool the cake in its tin on a wire rack, then remove from the tin, and peel off the lining paper.
8. Feed the cake once a week with orange liqueur. Do this by carefully pouring straight from the bottle, but if you prefer use a small ladle. Wrap the cake in clingfilm until ready to decorate.
9. This cake is best eaten within three weeks. To decorate, warm the apricot jam and, using a pastry brush, glaze the top all over. Arrange the fruit and nuts on top and glaze these too. If you like, highlight with a gold leaf for an extra special touch.