In a blender or mini food-processor, blend together all of the marinade ingredients to a fine paste. Taste and adjust the seasoning to taste. Pat the chicken dry with kitchen paper. Put it in a dish and rub the marinade all over it and if time allows let it rest for an hour or so in the fridge. Preheat an oven to 180C/350F/Gas 4.
Put the chicken in a roasting tin and baste with the marinade, reserving any extra. Bake the chicken for one hour. Cover the chicken loosely with aluminium foil after the first 10-15 minutes or the maple syrup in the marinade will burn. Baste the chicken a few times during cooking, adding some of the reserved marinade if it starts to look dry.
After the chicken has been roasting for an hour, check whether it is cooked. (The meat is cooked when a thin skewer or a thick needle inserted in the thigh joint produces a clear liquid.) Transfer to a serving dish, cover the chicken with foil and allow it to rest for five minutes before you carve it.
Meanwhile, strain the liquid from the roasting tin into a small pan, adjust the seasoning to taste and keep warm. Joint and serve the roast chicken alongside roast potatoes, drizzled with the juices from the roasting pan.