When Fornell has his photo taken by the machine at the laser tag range, his mouth was closed. In the photo on the ID card it was wide open.
When discussing Miranda Okafor with Tony, Abby refers to her as Michelle instead of Miranda.
When Abby shows the partial mailing label, there is "C-43" in the upper right hand corner. This is a code for USPS for route sorting. The label was addressed to a London address that would not use an American postal sorting code.
The British prison escapee talks about placing the woman's body in a "casket" but a box in which a body is buried is always called a "coffin" in the UK (the precise definition of the words notwithstanding) and he would use that term.
There are many prisons in England, Prickwillow Prison is not one of them.
The nearest prison to the tiny village (population approx 440) is over 15 miles away.
The route Ellie claims the escapees took involved them walking or possibly driving along the coast a couple of miles out to sea. The blue bits on maps are water.
Prickwillow is not, by any measure, "just outside London", it is 80 miles/2 hours away from the city.