Kavanagh was born in 1940 in Durban, South Africa, where her father was a journalist before and after his service as a fighter pilot in the SAAF during the Second World War.

She was hired by "A. D. Peters, a legendary agent who showed her the ropes",[1] taught her how to negotiate and gave her responsibility for selling serialization and newspaper rights for the agency's early group of clients, including Arthur Koestler, S. J. Perelman, Rebecca West and Tom Wolfe.

In the 1980s, Kavanagh left Barnes for a relationship with Jeanette Winterson, author of Oranges Are Not the Only Fruit, but later returned to the marriage.

[3] In 2001, her employer, now known as Peters, Fraser & Dunlop, was purchased by CSS Stellar, a company specializing in sports marketing.

[1] She died of a brain tumour on 20 October 2008 in London, aged 68, and was buried on the east side of Highgate Cemetery.