I'll comment more later, but like everyone else I was very sad to see that Elisabeth Sladen's name is now in the minus column as well.
20 April 1951: birth of Louise Jameson, who played the Fourth Doctor companion Leela from 1977 to 1978.
ii) broadcast and publication anniversaries
20 April 1968: broadcast of sixth episode of Fury from the Deep; last appearance of Deborah Watling as Victoria. The seaweed creature is destroyed by Victoria's screams, and she decides to stay behind.
20 April 1972: publication of The Making of Doctor Who by Malcolm Hulke and Terrance Dicks, the first book about the show.
20 April 1974: broadcast of fifth episode of The Monster of Peladon. Eckersley's treachery is revealed.