Properties in the Village District other than those zoned residential and properties zoned residential on which the principal use is not a residence shall be entitled to one roadside identification sign for each accessible road frontage and not more than two wall signs per business occupant, one visible from the street and the other, where all parking is located within the rear yard, visible only from the rear parking area. Such wall signs may be composed of multiple parts if building design makes such a multipart sign more consistent with Village District goals. Each such sign, including a multipart sign, shall not exceed the wall sign square footage specified in each zone, except for establishments having in excess of 50 linear feet of building frontage shall be allowed an additional one square foot of sign area for each five linear feet of building frontage; provided, however, that no such establishment shall have any such sign that exceeds 25 square feet in area.