Isobel Watkins
Isobel Watkins was a photographer and the niece of Professor Watkins. She was staying at the home of Professor Edward Travers when she met the Second Doctor, Jamie and Zoe. She assisted in the defeat of Tobias Vaughn and the Cybermen. (DW: The Invasion)
When Watkins went public with her story, C19 began harassing her, telling her to keep quiet. Her claims that Earth had been invaded by aliens were not believed, and her photographs of the Cybermen were dismissed as fakes. Months later, she was interviewed by James Stevens, who was investigating UNIT. (MA: Who Killed Kennedy)
She married Jimmy Turner, whom she met during the Cybermen's invasion. (MA: The Scales of Injustice)
Personality
Isobel was a feminist, and got very angry when she was told photographing the Cybermen was "no job for a woman" by Brigadier Lethbridge-Stewart. She got on very well with Zoe Heriot.
Behind the scenes
The events of Who Killed Kennedy can be viewed as a slight retcon, as The Invasion ended with her getting a lucrative job because of her photos of the Cybermen invasion.