1d Bright Scarlet BW #59bg variety Imperforate between stamp and bottom margin [Pos 111] used posthumously on 1928 Melbourne Philatelic Exhibition cover front, Cat $8,000.
Brusden White state this to be the rarest of the 1d Engraved perforation errors. [This is one of the only two known examples recorded in the ACSC. The plate position has been incorrectly transposed in the catalogue (at Page 5) and should read as (No 111 on sheet).] (Image1)

Estimate AU$4,600