Sierra Leone 1965 Churchill (30c) on 6d Climbing Lily, error, SG374bSierra Leone 1965 Churchill (30c) on 6d Climbing Lily, error 'AIRMAIL' '30c' OMITTED SG374b. A lower right corner block of 4 with '1A' plate numbers, unmounted mint, Post Office fresh with full original gum. Almost certainly a unique positional multiple of this major error, as it is believed only one sheet of 60 existed. Stamp issue related to the Commemoration of Sir Milton Margai (1895 1964) and Sir Winston Churchill (1874 1965) "in memoriam two