Panel two of page 1 shows the license plate number of Freeman's SHADOcar as JC-104.

On page 1 of the story, Freeman reports in to SHADO that he is about 10 miles west of Keighley. Keighley is a town in West Yorkshire, England.

Freeman is depicted driving his SHADOcar from the right-hand seat, as is the norm for cars designed in England. But the SHADOcars have typically been shown to have their driver's position on the left. And, in the TV series, even the roads of England are shown with cars driving in the right-hand lanes, despite England's tradition of the opposite up to the present day.

Foster wears an alien spacesuit in order to fool the aliens into thinking he's one of them. But on page 2 of the story, he removes his helmet to identify himself to Freeman, and no green fluid is discharged. It would make sense that Foster does not want to have to breathe the fluid if he doesn't have to, but does the helmet have some means of at least mimicking the green fluid effect while he's wearing it? The strip is in black-and-white, so we never really see. Possibly the helmet could have dual panes of glass built in so that fluid is contained between them, giving the illusion of a fluid-filled helmet.

On page 4 of the story, SHADO estimates the incoming UFO will land within a 20-mile radius of Manchester. Manchester is a large city in central England.

Foster is consistently referred to as Major in this story, but his rank has always been Colonel before.