From Wikipedia

Seven Up Series

Episode Two

Seven Up - Fourteen

The fourteen subjects are Bruce Balden, Jackie Bassett, Symon Basterfield, Andrew Brackfield, John Brisby, Peter Davies, Susan Davis, Charles Furneaux, Nicholas Hitchon, Neil Hughes, Lynn Johnson, Paul Kligerman, Suzanne Lusk and Tony Walker.

The participants were chosen in an attempt to represent different social classes in Britain in the 1960s. Apted admits in the commentary track of the 42 Up DVD that he was asked to find children at the extremes. Because the show was not originally intended to become a repeating series, no long-term contract was signed with the participants. The interviews since Seven Up! have been voluntary, although the participants have been paid an unknown sum for their appearance in each film, as well as equal parts of any prize the film may win, says Apted. Each subject is filmed in about two days, and the interview itself takes more than six hours.