23 is an exploded perspective view of a spanner member and a pair of lower wall panels. [0167]FIG. 124 is an exploded side view of an upper wall member, a pair of lower wall panels, a spanner member and a connector member. [0168]FIG. 125 is an exploded side view of a lower wall panel, an upper wall panel and connector members including a stand-alone hanger bracket. [0169]FIG. 126 is an exploded pe