Put the breadcrumbs in a bowl and add the milk. Leave for 5 mins, or until the milk has been absorbed. Add the lamb, lemon zest, garlic, spices, coriander stalks and plenty of seasoning. Mix everything well with your hands, then shape into meatballs, it should make about 30. Cover and chill the meatballs for at least 30 mins, or up to 24 hrs.