Finely chop half the olives. Combine chopped olives, mince, breadcrumbs, egg, oregano, half the feta in a bowl. Season with salt and pepper. Roll tablespoons of the mixture into 16 meatballs
Heat the oil in a large frying pan over medium-high heat. Add the meatballs and cook, turning occasionally, for 5-7 minutes or until cooked through.
Meanwhile, combine the yogurt, garlic and 1 tablespoon warm water in a small bowl. Season with salt and pepper. Cut the pita breads in half crossways. Using your fingers, separate each half to form a pocket.
Spread half the garlic yogurt inside each pita half. Fill with the rocket, tomato, the remaining feta and olives and the meatballs. Drizzle with the remaining garlic yogurt. Serve with lemon wedges.