8 March 1940: birth of Christopher Wray, who played PC Groom in The Dæmons (Third Doctor, 1972) and Leading Seaman Lovell in The Sea Devils (Third Doctor, 1973)
ii) broadcast anniversaries
8 March 1969: broadcast of first episode of The Space Pirates. Space Pirates are destroying navigational beacons; the Tardis lands on one and the pirates blow it up.
8 March 1975: broadcast of first episode of Genesis of the Daleks. The Time Lords send the Doctor, Harry and Sarah to Skaro, where Davros is experimenting.
8 March 1982: broadcast of first episode of Earthshock. Paleontologists disappear and the Tardis appears in an underground cave system, attacked by androids under Cyber-control.
8 March 1983: broadcast of third episode of Enlightenment. Turlough is rescued by the Buccaneer, whose captain invites the others over for a party.
8 March 1984: broadcast of first episode of The Caves of Androzani. The Doctor and Peri get poisoned, captured and (apparently) executed.
8 March 2002: webcast of "The Child, Part 1", fifth episode of Death Comes to Time. I'm just going to note the anniversaries to this in future, the plot is too peculiar to summarise.
8 March 2010: broadcast of Dream-Eaters, ninth episode of the Australian K9 series. K9 must figure out how to destroy an ancient alien weapon before everyone's dreams turn into a waking nightmare.
iii) date specified in-universe
8 March 1702: setting of Big Finish audio Phantasmagoria (1999)