Russell T. Davies makes the uncredited role of the radio announcer.
The triangle symbol represents the three families unified.
In Gwen's basement is a piebald (black and white) mouse. Breeding these fancy mice as pets is surprisingly popular in England, with associations devoted to the pursuit. In genetics/embryology research, the piebald mouse has helped scientists better understand a number of genetic diseases.
This episode takes place in May 2011, two months later.