From the Doctor Who News Page:
Dolore Whiteman has passed away at her home in Australia.
Dolore Whiteman had appeared in Doctor Who playing Tegan’s Aunt Vanessa in Logopolis, the Fourth Doctor swansong and Tegan’s introductory story.
According to IMDb she has 14 credits to her name with Logopolis her last ever work.
She was the mother of Tracey and Jodie Wilson who both appeared as the vocalist backing singers in the Seventh Doctor story Delta and the Bannerman.
Found out from a forum that I am in that she has been dead since September 2013.