These two exclusive 'Imperforate and Perforated' Reprints of the 1964 6d Thornbill stamp and its 1966 5c counterpart were released in the 2007 Prestige booklet titled, 'Behind the Stamp', compiled and edited by the renowned philatelist, Richard Breckon. The objective of the booklet was to highlight milestone precedents and marketing trends in the postal service as they evolved through time.
This issue reflects on the post office's intention to assist the public in familiarising themselves with the new conversion rates from 'Pounds and Pence' to 'Dollars and Cents', by re-releasing the 6d Thornbill stamp with the 5c denomination in the First 1966 Decimal Definitives series. (Note: for same reason, other select stamps from the last Pre-decimal definitive series were similarly re-released in the first Decimals edition).
Of added philatelic significance, the stamps are Micro-print dated, 2007, and the Perforated stamps are gauge 14 x 14 1/2 versus the Perf 13 1/2 for the original issues. See the other two images.
