We meet Veronica Honiton just briefly in Possession. She isn't a full-fledged character, really—she's one of the many peripheral figures whose voice appears in letters, essays, and other documents that are excerpted throughout the novel.
As we learn, Veronica Honiton was an early scholar of Christabel LaMotte's writings, and she published a "very slim and ladylike" book on LaMotte in 1947 (4.1). From what we see of her work, it seems clear that Honiton never imagined that Christabel LaMotte and Blanche Glover might have been lovers. On top of that, she disses The Fairy Melusine outright and states that LaMotte's epic poem has been "deservedly forgotten" (4.4).
Not to put too fine a point on it, but Honiton's only purpose in the novel is to give us readers a sense of the vast difference between women's scholarship in the late 1940s and women's scholarship in the late 1980s. Second-wave feminism this ain't. But we also get the sense that back in the 1940s, women may not have been allowed to write in an any other way, so we can't quite blame her.