Make a marinade by mixing the curry paste, yogurt and oil. Put the chicken in a non-metallic dish, cover with half the marinade and leave for at least 1 hour.
Put the couscous in a bowl, add the hot stock, cover and leave for 8 minutes.
Meanwhile, cut the pomegranate in half and remove the seeds. Add them to the couscous with the orange rind and juice.
Remove the chicken from the marinade, reserving the marinade, and transfer to a foil-lined baking sheet. Cook in a preheated oven, 190°C (375°F), Gas Mark 5, for 6—7 minutes, then transfer to a preheated hot grill and cook for 2 minutes until caramelized. Cover with foil and leave to rest for 5 minutes.
Roughly chop the coriander and mint, reserving some whole coriander leaves for garnish, and add to the couscous. Thinly slice the chicken. Spoon the couscous on to plates and add the chicken. Thin the reserved marinade with the lemon juice and drizzle over the couscous. Garnish with the reserved coriander leaves and serve immediately.