For the stuffing, make it well in advance. Prepare the turkey itself on Christmas morning, so it’s ready to go in the oven later. Once cooked, you can leave it to sit for 30 minutes before serving. Cover it in tinfoil and a tea towel to keep it warm and moist.
In a large frying pan melt the butter with the oil. Add the onion, garlic and celery and cook for 5 minutes until completely softened, but not brown. Place into a large mixing bowl.
Add the bread, parsley, thyme, tarragon, lemon, eggs, salt, pepper, raisins, walnuts and capers. Combine well with a wooden spoon or hands.
Wash and pat dry the turkey inside and out. Place the cut lemon inside the cavity. Fill the remainder with stuffing and also the neck, folding the skin under. Place the remaining stuffing into a greased baking dish. Tie the legs with string. Season the outside of the bird, then cover with bacon. Place into a large baking dish lined with paper. (All of this can be done the day before.)
Preheat oven to 170C. Remove the turkey from the fridge 1 hour before cooking. Place 2 cups of water in the base of the pan. Cover tightly with tinfoil and bake for 1½ hours. Remove the tinfoil for the remaining hour to allow the turkey to brown. Let it sit for at least 10 minutes before serving.