12 August 1969: birth of Nev Fountain, author of many tie-in media and Nicola Bryant's other half.
12 August 2003: death of Anne Tirard, who played Locusta the poisoner in the story we now call The Romans (First Doctor, 1965) and the Seeker in The Ribos Operation (Fourth Doctor, 1978).
12 August 2004: death of Alec Wallis, who played Leading Telegraphist Bowman in The Sea Devils (Third Doctor, 1972) and Warner the communications technician in Revenge of the Cybermen (Fourth Doctor, 1975).
ii) broadcast anniversary
12 August 2011: first showing of The Middle Men, sixth episode of the fourth series of Torchwood. Gwen and Rhys bust her father out of the Cowbridge camp, but when she reaches L.A. she gets a call to tell her that her family have been captured.
iii) date specified in-universe
Same picture as yesterday; apparently Wilmington emerged victorious over Kinsbroke on 12 August 1904, as seen in the 2008 Torchwood episode, From Out of the Rain.