After lunch at Emu Bottom it seems Fangio drove Skye, the Grey Blue Metallic (colour code 906) 6.9, on at least two hot laps of the Sunbury area with the following passengers:
1st 'lap':
Julio Jeldes (his interpreter)
Peter Anderson (Motor Manual journalist), and
2nd 'lap':
Then-motoring editor of The Age, Christopher de Fraga, hopped in the back, behind front seat passenger, 1967 World Champion Denny Hulme.
It doesn't make sense that Jeldes wouldn't be present on the second lap, so that would put 4 people in the car the second time around.
I'm assuming Sir Stirling Moss was driving the second 6.9, which might've been Jeff K's old car. Fitting that the car is a light green... However it can't be Moss Green since that appears too dark. Oh and Jeff's old car can't be Thistle Green, since that wasn't released until 1980. Could Jeff K's old car actually be Cypress Green? Or was that car not built until 1980 (which would rule it out of the Fangio media day altogether)???
https://www.w116.org/tech/colors/