The photo in post #12 was taken at Sydney on 16 August 1971 after the two HS-125s escorted the first Qantas 747 to the terminal. The aeroplane in the background is indeed a DC-4. In 1971 Qantas still had two DC-4s in service on the Norfolk Island route so it could be either VH-EDA "Pacific Trader" or VH-EDB "Norfolk Trader".
Rgds