From the context it appears she was told soon after.
‘ [11] The appellant telephoned the deceased's house at 1732, but received no reply. At 1740 he called again, and spoke to Alan Ovens, asking if the deceased was in. He was informed that she had left to meet him. He replied, "OK, cool". Ovens informed Judith Jones about this call’
So both AO and JuJ knew that Jodi wasn’t with Luke 40-50 minutes after she had left the house yet it didn’t raise alarm bells with them and they didn’t phone Luke again to check that she had got there.
Why was it thought suspicious that Luke, a young boy, failed to chase up what had happened to Jodi when her parents, the adults, didn't?
Double standards?
"double standards" The same as neither party chose to phone the other? That great divide between the two. Two sides.
Let's think about that in more detail. JuJ was under the impression that her daughter would be meeting with Luke, somewhere "up here" She didn't know where but certainly appeared not to have been in the belief that her daughter would be walking to Luke's on her own, down a path which her mother did not approve of her using on her own, thus had told her not to? - that a fair assumption?
Now that missing detail - much like AB's, giving an approximation of when she had arrived home, basing this on receiving a phone call from he husband "about half an hour after" Which actually turned out to be a longer period of time than half an hour - didn't it? as they started from the beginning, using those till and ATM receipts. She hadn't kept check of 'real' time - these were approximations.
Now AO and JuJ, what were they doing in that time frame between Jodi leaving and this phone call? Were they busy, had they lost track of time, more so why would they be keeping a check on the time? However, as above they give the same 'type' of information. Jodi had left, shortly after her leaving Luke phoned, I told him that "Jodi had already left to meet with her". They don't know the time of Luke's phone call however, they did not check, that is obvious as they did not stop and think 'oh wait a minute that was over half an hr ago, did they? But again, when these timings around phone calls are checked (by the shoddy police work) it turns out to be a longer period of time. However it is clear they are not concerned, why would they be as it is evident by their actions of not phoning Luke that they believe the couple had met. That they simply were not aware of how much time had passed?
On the other hand however, we have a boy who was very much aware of the time he had claimed to have been out of the house, he tells of the rough time of leaving (around 5.30pm) and of the time he had phoned his friends to meet up in the Abbey. We know he is aware of the time as he phones them back "chasing them up" It is such an such a time, "where are you?" - concern that his friends hadn't arrived on time? He phoned them back, didn't he.
So this boy, who claims (knows by his account) that his girlfriend will be using this path alone, she does not turn up, specifically makes the point that he had not walked further than 'Barondale cottage' Just idles away for nearly two hours and thinks "she is not coming out" "I thought you had grounded her again"
A search is organised, it is known and believed at this point that the couple had not met. Luke tells JuJ he had not seen her all evening, that she failed to turn up at his.
"at his" - Luke then offers to search the path.
Clear reason yet again - why suspicion fell upon LM, why he could not be eliminated.