When Erika is evaluating Henry, Henry calls the machine a " sub-sonic Oscillator" when in fact it is simply an old portable X-ray machine turned up to face Henry.
When Will and Henry are walking through the park, shortly after Will says his "Ma" was from Ireland, a crew member knocks a tree branch before Will and Henry get to the tree [approx time: 06:56].
When in Oldham England in the hospital, the plugs are US style plugs and not UK styles.