Christmas roast duck

Name: Christmas roast duck
Ingredients: 1.5kg/3lb 5oz potatoes, peeled and thinly sliced; 2 onions, thinly sliced; 500ml/18fl oz chicken stock; 1 x 2kg/4lb 8oz whole duck, giblets removed; 1 clementine, cut in half; 1 cinnamon stick; ½ tsp Chinese five-spice powder; 75g/2½oz butter; 1 head Savoy cabbage, leaves shredded; 50g/1¾oz dried cranberries; sea salt and freshly ground black pepper; 2 Bramley apples, peeled, cores removed, roughly chopped; 200g/7oz fresh cranberries; 5 tbsp cider; 2-3 tbsp caster sugar, to taste