Put the red wine, sugar, star anise, clove, cinnamon stick, allspice, vanilla pod and seeds in a medium saucepan. Stir together, then heat gently to dissolve the sugar. Turn up the heat and boil for 20 mins until reduced and syrupy. Strain into a small, sterilised jam jar and leave to cool completely. Will keep in the fridge for up to 1 month.