27 July 1925: birth of Harry Towb, Osgood in The Seeds of Death (Second Doctor, 1969) McDermott in Terror of the Autons (Third Doctor, 1971), whose death I commemorated a few days ago.
27 July 1944: birth of Matthew Robinson, who directed Resurrection of the Daleks (Fifth Doctor, 1984) and Attack of the Cybermen (Sixth Doctor, 1985).
27 July 2018: death of Alan Bennion, who appeared as Ice Lord Slaar in The Seeds of Death (Second Doctor, 1969), Ice Lord Izlyr in The Curse of Peladon (Third Doctor, 1972) and Ice Lord Azaxyr in The Monster of Peladon (Third Doctor, 1974).
ii) broadcast / performance anniversary
27 July 2008: broadcast (and performance) of Music of the Spheres in conjunction with the first Doctor Who Proms concert.
iii) date of real events, implicitly specified in canon
27 July 1794: Robespierre is arrested and shot, and the Tardis crew escape revolutionary France.
27 July 2012: launch of the Olympic Games, as seen in Fear Her (Tenth Doctor, 2006). Dale Hicks goes missing, but (like everyone else) is found again.