(snipped)
Thanks for all that, PT. With regard to your statement quoted above, a number of us looked at the online material and I remember the timetable showing that the bus travelled up Benaroon Drive in the afternoon only; the morning bus went straight up Batar Creek Road, past the end of Benaroon Drive without entering. Somebody pointed that out to you and I thought you acknowledged it; anyway I don't remember you disputing it. The (afternoon) route went as far as Ellendale Crescent, which would not take the bus past any part of William's grandmother's place, but we were not sure where it actually turned around, and it's possible that it did in fact proceed to where Benaroon turned the corner as that would have been a convenient place for the bus to turn. However, as I said, apparently not of a morning.
Another reservation I have with your idea about somebody looking for children who had missed the school bus, is that 10:30 is pretty late to be following a school bus; any child who missed a bus timed to get children to school before 9 is unlikely to have hung around the stop for 2 hours afterwards. If the morning route had been up Benaroon Drive, this might not have mattered so much, because the follower could have seen the children playing outside earlier and awaited his opportunity. But if William was picked up by someone trailing the morning route, the child would have to have wandered as far as Batar Creek Road, and William would definitely not have been observable on or from Batar Creek Road at the earlier time applicable to someone looking for missed-bus kids.