In a large bowl, combine the suet, brown sugar, flour, breadcrumbs, allspice, cloves, nutmeg, and cinnamon. Stir in the currants, sultanas, raisins, candied peel, almonds, chopped apple, and both zests until everything is well mixed.

In a separate bowl, whisk together the rum, barley wine, and stout. Beat in the eggs until smooth.

Pour the wet mixture over the dry ingredients and mix until evenly combined. The batter should look loose and moist; add more stout if it seems stiff.

Cover the bowl and refrigerate for about 12 hours.

Butter a 1-pint pudding basin and pack the batter in, leaving about 3/4 inch at the top for expansion. Cover with parchment and foil, making a pleat in the center.

Steam over a gentle simmer for 8 hours. Ensure to top up the water as needed.

Cool the pudding, re-wrap it, and store in a cool, dark place for up to a month.

On serving day, steam it again for 2 1/4 hours until hot.

Run a knife around the edge of the basin, turn out onto a warm serving plate, and optionally ignite the brandy to serve flambé style.

Serve warm with brandy butter, custard, or rum sauce.