BBM Yes she would be, and her account of the morning is detailed and helpful, but I don't remember her giving actual times about that part of the morning.Isn't the FM a good source?
If one or several people living in the next street spoke to doorknocking police and said, the postie delivered at 9.45am, wouldn't that establish her time in Benaroon Drive? It'd be easy to verify where she was, she's a potential witness, her timing would be of paramount importance because her usual delivery time is 10-10.30 am.
My postie usually comes between 10 am - 11am, but on occasion has come at 8.30am or as late as, 2.30pm.
Maybe they have verified the time postie was at Benaroon, but for some reason it hasn't been released. If the car heard by the Crabbs wasn't postie, there's an unaccounted-for person driving up that end of the street in a stop-start fashion; there's a good chance that person took William, as opposed to some alternative hypotheses such as that he was taken in a northerly direction initially on foot.