Combine sultanas and alcohol in a large bowl, cover and soak overnight (or longer).
Grease a pudding bowl or basin of around 3-4 cup capacity.
Cream butter, sugar and orange rind together until light and fluffy. Pour in orange juice and mix well.
Add eggs one at a time and beat well after each addition.
Stir in soaked sultanas.
In a separate bowl combine sifted flour, cocoa, baking powder and spices.
Fold this through the wet mixture. Lastly, stir in the breadcrumbs.
Pour into pudding basin and smooth the top with the back of a spoon. Leave at least 1 cm at the top for the pudding to expand.
Cover the bowl or basin with a lid or foil.
Place the pudding into the slow cooker. Pour in enough water to come 2/3 of the way up the side of the pudding bowl.
Put on the lid and cook for 5-7 hours on HIGH.
Remove the pudding from the slow cooker and allow to cool. Turn the pudding out and wrap well with plastic wrap followed by a layer of foil. Store in a cool, dry place or in the fridge.
The pudding can be served warm or cold. To warm the pudding, heat in microwave or slow cooker. If using the slow cooker, put the pudding back in the original bowl or basin, place into the slow cooker and pour in water as before. Cook on HIGH for up to 2- 3 hours.