Malcolm Wainwright

Malcolm Wainwright was the grandson of Kathy Nightingale and Ben Wainwright. He delivered a letter from his deceased grandmother to Sally Sparrow in 2007. The letter explained that Kathy had been sent back in time to 1920 by a Weeping Angel. The Kathy in the present day was secretly witness to the delivery before she disappeared, thus knowing when and where to send her grandson to deliver the explanatory letter.

Malcolm's great-uncle was Larry Nightingale, who was Kathy's brother. Later on, Sally walked off with Larry, which could suggest that one day Sally would be related to Malcolm. (DW: Blink)