Australia 1964, 50th Anniversary of the first Australian Airmail Flight, 5d olive-green, SG370a, upper left corner block of 16 (4x4) lower right stamp (R4/4, upper right plate) showing 'Re-entry' to second 'A' of 'AUSTRALIA'.
Superb quality unmounted mint with full original gum.
A scarce positional piece and visually attractive.
The Stanley Gibbons catalogue value for a single example of the stamp showing the re-entry variety is £275.
