A couple of things: The boy is young for his school year group, having a July birthday, so most of his friends had already turned 16, some possibly close to 17 if they were September birthdays.
The family have a house in Devon but also mostly live in Notting Hill. He's used to negotiating London.
Social Services became involved because Kirstie had put the trip on Twitter and someone dobbed her (and presumably the father) in.
At 16, with no mobile phones etc, my family sent me off alone to visit my penfriend in France. I'd never been abroad. travelled from LHR to Paris, spent several hours looking at the sites with a girl I'd met on the plane then safely caught my train from Gare du Lyon to Montelimar. I think this boy would be perfectly fine. I'll I let my daughter, at 18, take her car and her boyfriend to Holland and then on to southern France, via Paris. I quake at the very idea of it now but the only dodgy moment was when I had a postcard from her saying that driving round the Arc de Triomphe was a bit hairy!