The Exchange Program
The last RAF exchange crew of that era finished with the RAAF in 1968. This exchange had been operating since the end of WW11. The RAF crews were operating with 36Sqn, RAAF flying the C 130As and while they were probably not tasked directly into Vietnam some may have "passed by" after completing a mission from Butterworth to Ubon and returning to Butterworth via Vung Tau where the RAAF Caribous were based. Ubon in those days was part of the SEATO arrangement.
I was in the last exchange group of 2 pilots and 1 navigator serving with 267 Sqn flying the Argosy. We returned to Australia in July 1968. While there may have been restrictions on where RAF crews could fly with the RAAF there were also restrictions on where we could fly with the RAF.
The RAAF transport exchange after this period was with the USAF until both the RAF and the RAAF acquired the C 130J.
Many ex RAF pilots flew with the RAAF during the Vietnam conflict on both the Caribou and the Canberra