SIERRA LEONE 1965 Margai 15c on ½d Fireball Lily, error, SG373bSierra Leone 1965 Margai 15c on d Fireball Lily, error portrait DOUBLE, ONE INVERTED, SG373b. Pristine unmounted mint example with full original gum. Stamp issue related to the Commemoration of Sir Milton Margai (1895 1964) and Sir Winston Churchill (1874 1965) "in memoriam two great leaders". Sir Milton Margai was prime minister of Sierra Leone from 1954 until his death in 1964. A rare and most peculiar error. The Stanley Gibbons catalogue value is