Preheat the slow cooker if necessary; see the manufacturer's instructions. Pour the wine, apple juice, water and orange juice into the slow cooker pot.
Add the sliced orange and lemon, the cinnamon stick, cloves and bay leaves, then mix in the sugar and brandy.
Cover with the lid and cook on high for 1 hour. Reduce the heat and cook on low for 2–3 hours, or set to auto for 3–4 hours, until piping hot. Ladle into heatproof glasses.