http://www.cmj.com/images/news/2005/nov/isobel-cambell.jpg
and indeed on the Wikipedia entry about her.
The thing that struck me about the picture in the magazine and, if anything, it is more striking in the picture linked to above, is that everything about the photo - her hair, her expression, her top, the background and the harsh lighting - screams Patrick Troughton era Doctor Who.
I think she is probably not an assistant, but is helping the doctor and expecting a baddie to come through the door in any second...