This is an EXTREMELY RARE British Field Post Office issue that has been cashed at Maldon,Essex (England).
Unfortunately,the date on the English datestamp can't be read.
This Christmas Island is the one which was part of the Gilbert & Ellice Islands,which later divided into the Gilbert Islands & Tuvalu in 1976.The Gilbert Islands became the independent Republic of Kiribati in 1979.
Christmas Island is now known as 'Kiritimati' (pronounced 'cirisimas') in the Gilbertese language.
It is not yet known when postal orders were discontinued in Western Samoa,but it is possible that Apia was the only post office in Western Samoa that was issuing postal orders.
Issued at Port Moresby on the 4th. of October 1967.
Papua & New Guinea were 2 separate territories under a common administration from 1952 until 1973 as the Territory of Papua & New Guinea when both territories united to form the Territory of Papua New Guinea in preparation for independence,which was duly attained in late 1975.Papua New Guinea remains an independent Dominion today.