Place cut vegetables on a baking sheet and drizzle with some olive oil and season with salt and pepper to taste. Place in oven and roast for about 10 minutes. Place couscous in a heat proof bowl and stir in all the spices and orange juice. Bring the vegetable stock to a boil and pour over the couscous making sure it covers the couscous mixture completely. Cover with a plate or plastic wrap and leave for 5 to 10 minutes or until all the stock is absorbed. Stir in the herbs, olive oil, grated lemon zest and juice. Fluff the couscous with a fork and toss with roasted vegetables.