Preheat the oven to 200°C (400°F, gas mark 6). Remove the giblets (saving the liver) and any excess fat from the goose, then dry the bird inside out with kitchen paper or a dry cloth. Season well and fill the cavity with the garlic bulb and three whole apples. Chop up the liver and stir into the stuffing. Stuff the neck flap and secure with a cocktail stick. Set the remaining stuffing aside to make stuffing balls.
Put the goose on to a wire rack in a large roasting tin. Cover the wings with foil to prevent them from burning and place in the oven. After 30 mins, lower temperature to 180°C (350°F, gas mark 4) and cook for a further 3 hrs. Let the goose rest for 20 mins before serving.
Meanwhile, core the remaining apples and cut into thick wedges. Melt the butter in a frying pan over a low heat. Add the sugar and stir until dissolved. Add the apples and bay leaves and cook for 10 mins until golden. Place the goose on a serving dish and surround with the apple wedges.
For the gravy, pour all but 2tbsp of fat out of the roasting tin. Add the flour to the tin and stir over a low heat for 1 min. Take the garlic and an apple from inside the goose. Cut the garlic bulb in half and squeeze the roasted paste from the cloves into the tin.
Halve the apple and scoop out the fluffy purée. Stir into the tin, then slowly add the chicken stock, whisking as you go. Simmer for 2 mins until thickened, then season. Strain before serving.