Preheat the oven to 220°C. Place the pork belly on a rack in a roasting dish, skin side up. Combine the salt and Chinese five spice. Rub the mixture into the skin then pour in enough water to fill the pan to just under the rack. Place the pork in the oven and roast for 30 minutes until the skin is crispy. Reduce the oven temperature to 180°C and continue roasting for a further 2 ½ hours or until the meat is very tender. Top up the water if necessary. Meanwhile, place the chicken stock, brown sugar, vinegar, star anise and lime juice in a saucepan. Bring to the boil then simmer for 10 minutes until the sauce is slightly syrupy. Remove the star anise. To serve, cut the pork into bite size pieces and place onto a platter. Drizzle with the dressing and scatter over the Thai basil and chilli. Serve with extra lime wedges.