I think it's interesting that there were, in fact, three claimed sightings - two of Jodi, and one of someone who could have been Jodi (the Andrina Bryson "sighting.")
The first two were after 5pm (between 5.05 and 5.10pm), placing Jodi on the Easthouses Road, a few minutes away from the Easthouses entrance to the path, meaning there was not enough time between those sightings and the claimed time of death of 5.15pm (Jodi would have needed a minimum of 8 minutes at a "brisk pace" to get to the Entrance to the path, and from there to the V break, taking the time to 5.13 - 5.18). We know from the evidence that the beating/strangulation before the fatal cut-throat injuries took place on the woodland side of the wall so, however it's presented, these sightings rule out a 5.15pm time of death and, as a result of other timings, rule out Luke as the killer.
But it's the Andrina Bryson sighting which interests me most. Firstly, Mrs Bryson placed the timing of her sighting much later (5.30pm 5.40pm) She based her timing on a call from her husband - she had been home for about half an hour, had unloaded the car and put away the shopping and had started cooking dinner, she told police. In her next statement, she produced her phone to show officers the time the call came in from her husband - 6.17pm, meaning she had returned home, after her "sighting," at 5.50pm.
The till receipt (originally) was timed at 16.45 - the prosecution allowed just 5 minutes for her to get out of the store, load up the car (with two small kids) and drive the 12 - 17 minutes to the point where she made her sighting - that's, absolute minimum, 5.02pm - 5.07 - 20 - 25 minutes before her earlier estimates, but still after 5pm. (In my opinion, the 5.30 - 5.40 timing is much more likely to have been accurate because (a) she would have needed more than 5 minutes to get out of the shop, load up the car, etc, and she was looking for a house that was for sale, so drove slowly into and out of a couple of streets - that wasn't factored into the police "timing" of her route.)
But here's where it gets crazy - police investigators "discovered" the time on the till receipt was wrong - it should have read 4.32pm. Taken with other timings, this means she did a large shopping, with two small children and had cleared the checkout in just 17 minutes. But without the till receipt being 4.32, she could not have made her sighting between 4.49 and 4.54pm - any time after that, and they could not have claimed Luke was the killer.
Sorry it's a bit confusing - I'm having to rush this as I have other work I need to do.