b'18167 173167** 9d Violet Plate 4 Ash N over N imprint block of 4 with Die II Substitution at [R49], right-hand units well centred, uniformly toned gum, MUH, BW:28(4)z - $1500 (as mounted mint) $500750168168* 1/- Blue-Green Ash N over A imprint strip of 6, row of skipped perfs at top, well-centred with full perfs,mild uniformly toned gum, MLH, BW:34(4)z - $900 (as an imprint block of 4) $400500169169C 1931 usage of 5/- Grey & Yellow Orange (plus 6d Kingsford Smith & KGV 1d Green) tied by Air Mail SYDNEY 23AP31 datestamp to commercial flight cover addressed to Portland Cement Co in England, endorsed Per Australia-England Experimental Air Mail 24-4-31, with flight cachet in violet, minor edge blemishes & vertical fold clear of stamps, BW:45 - $1200 (on cover).$400600'