The police will be able to tell from the phone masts whether LH and SB were together in this. But I don't know how long it takes for that kind of investigation to come back. And they will also know when and where Kayleigh's phone was last used.
Still don't know if that contact with her parents on Saturday morning was a text or a call. Different papers say different things. If it was a text, I wonder if it was in her usual way of texting, parents would know her style. I can't get away from the sense that she died on the Friday night if her phone was found on Saturday afternoon. I think a murder or struggle in the park during daylight hours would be highly unusual. If her phone was found after the Saturday, and she did phone her parents, then it is more likely she died on the Sat night.