Preheat the oven to 200°C/fan180°C/gas 6. Mix together the oil, spice blend, salt and lime zest and juice to make a paste. Rub the mixture evenly onto the chicken skin.
Pop the lime halves into the body cavity, along with the lemongrass, ginger and lime leaves. Sit in a roasting tin and roast for 1½ hours, until the chicken is cooked through. Tip any juices inside the body cavity into the tin, then lift the chicken onto a plate and rest for 5 minutes.
Meanwhile, pour off the fat, then stir the coconut cream, stock and curry paste into the juices left in the tin, and cook in the oven for a further 5 minutes, until hot. Carve the chicken and serve with the coconut gravy and some steamed greens, such as pak choi, and rice.