To make the stuffing, place the coriander, coconut, chillies, garlic and ginger in a food processor and process until finely chopped. Stir in olive oil, lime juice and sugar. Set aside.
Preheat oven to 220oC. Rinse chicken and pat dry. Trying not to tear the skin, carefully slide you fingers underneath the breast skin to loosen down to the thigh area. Push stuffing under the skin and spread until it forms a thin layer over the breast meat. Tie the legs together with kitchen string.
Place the chicken in a large roasting pan, breast side up. Drizzle with oil and season well. Roast for 20 minutes, then reduce the temperature to 200oC. Roast for a further 1 hour and 15 minutes, basting occasionally, until the juices run clear when you prick the thickest part of the thigh. Remove from oven and rest for 10 minutes, loosely covered with foil.
To make the gravy, remove fat from the pan juices until just the juices are left behind. Place pan over medium heat (if stove top safe). Add the curry paste and cook for 2 minutes or until fragrant. Stir in the coconut milk and simmer for 4 minutes until the sauce has thickened. Stir in the lime juice, fish sauce and sugar and then season to taste. Keep over a low heat until ready to serve.
To serve, carve the chicken and divide amoungst plates. Drizzle with the coconut gravy. Serve with lime wedges and steamed vegetables.