Gently ease the skin around the neck and breast of the chicken away from the meat using your fingers, reaching as far down the legs as possible. Set aside.
For the bread stuffing, heat the butter in a frying pan over a medium heat. Add the onion and fry for 2-3 minutes, or until softened.
Add the spring onions and garlic and cook for a further 2-3 minutes, or until softened.
Add the nutmeg and breadcrumbs and continue to fry until the breadcrumbs are crisp and golden-brown.
Add the thyme leaves, lime zest and juice, rum and sugar and stir well until combined. When the ingredients have warmed through and the sugar has dissolved, remove the pan from the heat and set aside.
When the bread stuffing mixture is cool enough to handle, push small handfuls of it under the loosened skin of the chicken, until all of the bread stuffing mixture has been used up. Tuck any loose neck skin into the cavity of the bird. Set aside.
Preheat the oven to 190C/375F/Gas 5.
Meanwhile, for the tomato and plantain stuffing, melt the butter in a separate frying pan over a medium heat. Add the plantain and fry for 4-5 minutes, or until tender.
Add the tomatoes and continue to fry for 4-5 minutes, or until the tomatoes start to break down and the sauce has thickened. Season, to taste, with salt and freshly ground black pepper.
Stuff the cavity of the chicken with the tomato and plantain stuffing. (Alternatively, cook the tomato and plantain stuffing in a small roasting tray for 25-30 minutes while the chicken is cooking.)
For the roast chicken, smear the butter over the skin of the stuffed chicken and sprinkle over the cayenne pepper. Season, to taste, with salt and freshly ground black pepper.
Place the chicken into a large roasting tin, then transfer to the oven and roast for 1½-1¾ hours, or until the juices run clear when a skewer is inserted into the chicken where the thigh meets the body.
Meanwhile, for the pumpkin rice, bring the water, pumpkin, two sprigs of thyme and salt to the boil in a large, covered pan, then reduce the heat until the mixture is simmering and simmer for 8-10 minutes, or until the pumpkin is tender.
Remove and discard the thyme sprigs, then mash the pumpkin and cooking liquid together using a potato masher, until the pumpkin breaks down. (NB: The mixture does not have to be mashed until smooth.)
Add the rice to the pan with the pumpkin mixture in it and stir. The liquid should cover the rice by 2-2½cm/1-1¼in, so add more water as necessary.
Add the butter and stir until melted, then cover the pan with the lid and return the mixture to the boil. When the mixture is boiling, immediately reduce the heat to a simmer. Cover and simmer on a low heat for 18-20 minutes, without removing the lid, until the bottom of the rice has browned slightly and all of the rice is tender.
When the rice is cooked, add the remaining sprig of thyme, then turn off the heat and leave the pan on the residual heat for a further 3-4 minutes.
When the chicken has cooked through, transfer it to a warm plate and cover with aluminium foil.
For the gravy, add the chicken stock to the juices that collected in the roasting tray and bring to the boil, scraping up any browned bits up from the bottom of the tray using a wooden spoon. Simmer the gravy until it has thickened, then sieve, reserving the liquid.
Heat the rum in a frying pan over a high heat, then remove from the heat and set alight using a match. Allow the flames to flare up, then die down. (NB: keep flammable objects away from the flame.) Pour the rum over the roast chicken.
To serve, carve the roast chicken and divide it among six serving plates. Place a portion of the tomato and plantain stuffing on top of each serving. Spoon the pumpkin rice alongside. Drizzle over the gravy.
