Use a fork to prick the goose all over. Do not go into the meat, just through the skin. Season inside and out with sea salt, stuff with the orange, lemon and apple; tie the wings behind the bird with cooking twine. Place breast-side-down into a roasting tin and fill with 1.25cm of water.
Bake in the preheated oven for 45 minutes, then remove from the oven. Turn the goose breast-side-up and prick the skin with a fork again. Add water to the tin to bring the level back up to 1.25cm. Return the goose to the oven and cook until an instant-read thermometer inserted into the thickest part of the thigh, near the bone reads 75 degrees C, about 2 hours. Remove from the oven and cover loosely with foil to rest.
Spoon 2 tablespoons of goose fat from the roasting tin into a small saucepan and heat over medium heat. Stir in the cherries and cook until the cherries have softened and begun to release their juice, about 10 minutes. Stir in the port wine and bring to the boil over high heat. Boil for 2 minutes, then stir in the ginger, spring onions, sugar, soy sauce and chicken stock. Return to the boil, then reduce heat to medium and simmer until the sauce has reduced by half or to your desired consistency, about 10 minutes. Serve the sauce alongside the goose.