That’s the first time I’ve heard the phone in the grass info. That reminds me of a night out around years ago. I got home and realised I had left my phone in the taxi. It was a cab I had hailed outside the bar so I didn’t know the company or number (not smart I know, I’m wiser these days) The car was very distinctive though - more like a small white minivan, and I really wanted and needed my phone back so I got another taxi from a local company back to the bar and sat outside for a while looking out for the original cab. Luckily for me it wasn’t long before I spotted him, he hadn’t had anyone else in the back seat yet and my phone was on the floor of his car. Longshot, but perhaps Libby got to the door and in fumbling for the (perhaps lost?) key, she dropped her phone in grass. Couldn’t find it because of the dark - no phone to use as a torch. Made her way back to the bench to see if she can see her taxi driving up/ down the road again. Becomes upset at being locked out/ cold/ no phone/ no key/generally horrible night. Still has enough wits about her not to accept help from stranger in car. Then any number of possibilities after that...maybe someone she knew passed by and offered to help her look for the phone in the street - which could lead into the “scream” the neighbour heard if something went wrong.