Preheat oven to 425°F. Cut off lumps of excess fat from underside of chicken. Rub skin with cut side of garlic, then with the rosemary, lemon wedges and olive oil; don't discard when finished. Season inside and outside of cavity with a little salt and pepper. Stuff with the pieces of garlic, rosemary and lemon that you rubbed the chicken with, and chili flakes.
Place in roasting pan. Bake for 10 minutes, then turn heat down to 375°F. Cook till juices run clear, about one hour and 15 minutes.
A meat thermometer inserted into the thickest part of the thigh (but not touching the bone) should read 185°F or 85°C. Let rest 15 minutes before cutting up and serving.
Per serving for six: 412 calories, 35 g protein, 29 g fat (8 g saturated fat), 3 g carbohydrates, 1 g fibre, 0 g sugars, 138 mg cholesterol, 130 mg sodium