Put the lamb in a non-metallic dish. Mix together the ras el hanout, lemon rind and juice, garlic and oil. Season to taste with salt and pepper and rub the mixture all over the lamb. Leave to marinate for at least 1 hour.
Cook the lamb under a preheated hot grill, turning once, for about 2 minutes each side, until it is browned and cooked to your liking.
Meanwhile, pour the boiling stock over the couscous, cover tightly and allow to absorb the liquid for 5 minutes. Fluff it up with a fork.
Toss the apricots and coriander through the couscous and serve with the lamb.