In fairness to Jodi's mum, the description wasn't issued until late afternoon on July 4th and again on the morning of July 5th. Dickie contacted the police on the afternoon of July 5th, so there wasn't really time for Judith to do anything.
David Dickie, however, not only knew his son was on the path, but he, himself was on the path later that evening and failed to come forward about his own presence there - as I understand it, his presence only became known after his son spoke to the police on July 5th.
So, descriptions aside, he knew Ferris and Dickie were on the path for 5 days and he knew, for the same time period that he was on the path that night, and failed to say anything.
The stories surrounding DD's presence on the path are mind blowing. He might have been home when Ferris and GD got back to the house, but he might have been walking the dogs (which meant he was in the woodland strip directly after the murder). But, according to other statements, he might have walked the dogs later in the evening - maybe 6 o'clock, maybe around 8 - 8.30pm. He did, definitely, walk the dogs, in the woodland strip on the afternoon/evening of June 30th, sometime after 5.15pm. He did, definitely, go through the V break in the wall with 8 dogs, it's just that nobody can remember exactly what time that happened, other than it was after 5.15pm.
A couple of other interesting connections. If he walked the dogs at 8.30pm, it's a tad surprising he didn't stumble across one James Falconer having his solo intimate moment, or on his way to do so, or on his way back, since JF claims to have been in the woodland strip, doing his thing, around 8.30 - 9pm.
If it was just after 5.15pm, it's surprising DD didn't stumble across the kids playing in the woodland strip, heard shouting and laughing with each other, between 5.10pm and 5.25pm. Or the dog walkers who reached the junction of the paths at around 5.15pm, who changed their minds about walking their dogs in the woodland strip and turned around and headed for home.
It was a busy area that evening, no doubt about it.