The night before you want to make the pudding place the raisins, currants and sultanas into bowl. Chop the figs and dates so they are roughly the same size as the rest of the fruit and add to the bowl, along with the grated apple. Pour over the rum or brandy and mix to combine. Cover the bowl with cling-film and allow to soak overnight.
The day after place the butter, sugar and treacle into a bowl and beat together until light and fluffy, about 5 minutes. Add the eggs one at a time and once fully combined fold in the flour and spices. Add the fruit and fold together to combine.
Grease a 1-litre pudding bowl with a little softened butter and then scrape the batter into the bowl. Cut a piece of foil and make a fold in the middle to make a pleat. Cover the basin with the foil and secure with a piece of parchment paper. Place a large bowl upside down in a large saucepan and place the pudding in top. Fill the pan with enough water so it comes up halfway up the pudding. Cover the pan with a lid and place over high heat and bring to a boil, then reduce the temperature and simmer for 2 hours.