Preheat the oven to 180C / Fan 160'C / Gas Mark 4.

Peel and chop the onion into quarters. Peel the potatoes and cut them into halves or quarters so they are in approx 2-3 inch chunks.

Place the chicken in a large roasting pan. Arrange the potatoes, onion, chantenay carrots and whole (unpeeled) garlic cloves around the chicken.

Cut the orange in half. Juice one half and mix the juice with the other marinade ingredients.

Cut the other half of the orange into four chunks and stuff these inside of the cavity of the chicken, along with the juiced piece of orange peel.

Pour the marinade evenly over the chicken and vegetables. Mix to coat the veg and then place in the oven for 1 hours and 15 minutes, basting the meat and veg once or twice during this time.

After the given time, take the chicken out of the oven and check it is cooked. I like to do this using a meat thermometer (should be around 75'C) in the thickest part but you can also pierce it with a skewer and see if the juices run clean. If they don't put back in the oven for another 15 minutes and then check again.

Once cooked, remove the chicken from the oven and cover with foil. Leave to sit for around 5-10 minutes before carving up and serving. The garlic cloves can be 'popped' from the skin and 'mushed' over the meat and veg - use any leftover liquid as a sauce.