Take chicken out of the fridge 30 minutes before cooking.
Preheat oven to 220C.
In a small bowl mix together the softened butter with the rosemary, thyme, fennel seeds, chilli flakes, salt and pepper.
Squeeze the juice of the lemon over the chicken.
Gently separate the chicken skin above the breasts from the flesh, creating 2 pockets. Stuff each of the pockets with 2 tablespoons of the herbed butter. This will ensure the breast meat is extremely moist and flavoursome. Carefully pull the skin back over the breasts so no flesh is exposed.
Rub the rest of the herby butter all over the chicken, inside and out.
Place chicken in a large baking dish, breast side up, and stuff with lemon quarters, garlic and extra rosemary and thyme sprigs.
Put the chicken in the oven and immediately reduce the temperature to 120C (fan-forced).
Roast for 3 and 1/2 hours, basting every hour, until the chicken is golden brown.
Let the chicken rest for at least 15 minutes before carving and drizzling with the delicious pan juices.