In addition to the foregoing, a sign or signs referring to or advertising the premises upon which it is located or displayed, or to the identity of the occupant thereof, or to a service rendered thereon or therein, or to a product or item available therein, or to a trade, business or profession carried thereon or therein; one such sign may be erected on any entrance wall and one on any wall facing on a street, and one on any wall facing a municipal or public parking area, and shall be erected parallel to the face of such wall, not extending more than 12 inches from the face of said wall shall have the bottom of said sign structure not less than eight feet above the ground level.