None that I noted.
ii) broadcast anniversaries
18 December 1965: broadcast of "Coronas of the Sun", sixth episode of the story we now call The Daleks' Master Plan. The Doctor, Steven and Sara give Chen a fake tarranium core; and land somewhere with a really poisonous atmosphere.
18 December 2003: webcast of sixth episode of Scream of the Shalka. The Doctor blows up the Shalka with Alison's help. (And there's a rather peculiar bit with the Master, but watch and judge for yourself.)
iii) date specified in canon
18 December 1953: disappearance of the Sky Gypsy flying from Dublin to Cardiff (see yesterday's Torchwood anniversary).