South Africa Postage Due 1927 2d Dramatic Misperforation Strip

POSTAGE DUES: 1927-28 2d black & purple (SG D19a var). F/M bottom left corner strip of six showing a dramatic MISPERFORATION ERROR throughout the lower margin. Also plate flaw WHITE BLOB above "U" in DUE on third stamp. Sympathetic perf support at rear. Great error block. See additional image below.