Andrew Hunt, the author of Cat's Cradle: Witch Mark, was a veterinarian (and Doctor Who fan) who wrote in his spare time. He was one of the first previously unpublished authors to be commissioned to write one of the Virgin New Adventures.
He claimed to have gone to great lengths to ensure the Seventh Doctor and Ace remained in character, particularly in terms of their dialogue. He also expressed regret at not having more opportunity to make last-minute amendments to the manuscript prior to the novel going to press.