Fenn studied Linguistics and Astronomy at the University of Hertfordshire, where she became the president of PSiFA (the local student Science Fiction society) from 1984-1985. She also helped organised Shoestringcons and edited their newsletter/fanzine, Hypo-Space, for a period.
Fenn has had several short stories published in various magazines and anthologies. Her debut novel, Principles of Angels was published in June 2008 (UK) and is the first in a series of linked novels. Her second novel, Consorts of Heaven, published in June 2009, mixed elements of fantasy with science fiction and was not a direct sequel. The third book, Guardians of Paradise (2010) brings together threads from the first two. Two further books in the Hidden Empire series have been contracted for.