a decision was made in May 1968 to constrcut an airstrip on Lord Howe Island. It was to be 4,200 feet [1,280m] in length and suitbale for use by a Fokker F27
Lord Howe Island was planned as being suitable for the DHC8. The F27 was never mentioned for Lord Howe.
Not sure if my history is correct here, but didn't the strip at Lord Howe open in the 70's? The Dash8 didn't fly until the 80's.
The Dash7 however, first flew in the mid 70's, and would fit the timeline!
I recall a Dash7 doing a demo tour around QLD during the late 70's.