Grease nad line a deep cake tin of the correct size with non-stick baking paper or use a non-stick cake tin. Ensure all the ingredients are at room temperature. Pour the rum over the saltanas and leave to infuse for 1 hour.
Preheat the oven. Sift the flour together with the spices and the bicarbonate of soda. Beat together the sugars, sunflower oil and eggs until smooth. Stir the spiced flour into the smooth mixture, then add the remaining ingredients (including the glacé ginger, if using) and stir well.
Spoon the mixture into the prepared tin and bake for the time stated or until a skewer inserted into the middle of the cake comes out clean.
Make the syrup while the cake is baking. Strain the juices into a jug, add the sugar and stir well. Continue to stir at intervals while the cake is in the oven. As soon as the cake is out of the oven, pierce it with a skewer several times, then careully spoon or pour the citrus syrup over the top. Leave the cake to cool before removing it from the tin.
To bake: Fan 130°C (250°F) or conventional 150°C (300°F) gas mark 3 for 3 hours.
To store: Keeps fresh for up to 2 weeks if covered and decorated with icing or wrapped in greaseproof paper and kept in an airtight container. Or to freeze for up to a month, wraooed in a double layer of greaseproof paper and aluminium foil.