Preheat grill or grill pan to medium-high or broiler with oven rack set on second level from the top of oven.
Combine 1/4 cup olive oil, just eyeball the amount, with spices and grill seasoning in a shallow bowl or dish. Add lamb to seasonings and coat evenly in the mixture. Skewer the meat on metal skewers and let sit for 10 minutes. Cook on a hot grill or under the broiler for 7 to 8 minutes for medium-rare.
Thread the onions and peppers onto skewers, drizzle with oil and sprinkle with salt and pepper. Place on grill or under the broiler for 12 to 15 minutes or until tender.
Combine yogurt with garlic, mint and parsley.
In a sauce pot toast pine nuts over medium heat, remove and reserve. Add butter, zest of lemon, and chicken stock to pot and bring to a boil. Stir couscous and olives, cover the pot and remove from heat. Let the couscous stand 5 minutes. Fluff couscous with a fork and toss in the pine nuts.
Stir the lemon juice into yogurt to thin.
Serve meat and vegetables with dipping sauce, couscous and toasted pita alongside.