I believe the explanation for the two cars is simple: both cars are owned by the Sharpley family. The grey sedan is the father's, and the white Starwagon (NOT a station wagon, but close to the description given by FM) is Anne-Maree's car. The FM's description even tells of how the white vehicle doesn't slope down at the back but is more abruptly angled. FM's description tells of these cars being seen from around 6:30 in the morning. The testimony of both Sharpleys is that Mr S went to work just after 6:30am, and that his grey sedan was parked (nose pointing up Benaroon Drive). Both he and she say they saw no strange cars there that day, and both drove out looking for possible traffic. It's not clear whether Anne-Maree's car was parked in the driveway or on the roadside, but FM may have been mistaken about their exact positions. The three critical reasons I believe these are the two cars are: 1) They are reasonable matches of the descriptions 2) No one else saw any 'strange' cars 3) The police didn't release the info for a year - suggesting they had initially come to the same conclusion, then re-thought about it when Tony Jones came into the frame. An important fact here is that the 'oddness' that struck the FM about the cars was that they were supposedly parked between two driveways. She took this to mean 'between two properties'. But guess what? The Sharpley house has two distinct driveways - the cars were parked between them.
