Multiple reports given to investigators who traveled to the area, a mention of it being reported in the media, and a map showing physical evidence.

So far I have not found where this encounter was reported in the media.

The investigators who traveled to the area are Mr S Briggs and Mr A Fiannaca, independent(?) ex members of the Perth UFO Research Group, as mentioned in ACOS Bulletin #2.

As mentioned at the end of the above Bulletin 3 article, there would be a follow up in Bulletin 4.

“When results are are hand, we will advise everyone” I await them.

A further addition of information was published in Bulletin 5 (March 1976)

Sources & Links:
ACOS Bulletin 3, September 1975
ACOS Bulletin 4, December 1975
ACOS Bulletin 5, March 1976.