Children of Earth: Day One - S3-E1
Character mistake: Lois says that Colonel Aduya's uniform "isn't British Army". In fact, it is entirely (and accurately) British Army with the exception of the small UNIT badge over the pocket.
Children of Earth: Day Two - S3-E2
Character mistake: When lanto is in the park and the children all stop the camera shifts to look at a little girl in pink. But in the top left corner there is a young blonde girl still moving and looks to be silently mouthing a word as she steps off the roundabout. (00:32:08)
Answer: Several times during the episode, most notably at the beginning when the old grave is discovered, Tosh holds a devise that looks a great deal like the Sonic Screwdriver that she uses to determine the age of the skeleton. However, a search of Google images shows that it is not the same thing.
OneHappyHusky