Seymour was born in August 1970, in London. She had a brother and was raised in
Broadstairs in
Kent, where her parents Barbara and Richard ran a convience store. She went to
King's College, Cambridge, reading music. Following her graduation from the university in 1991, Seymour enrolled at the
University of Kent. From 1999 and 2000, Seymour was the first woman to be appointed visiting lecturer in British studies at the
University of Tokyo and lasted in the post for two years. She later began her teaching career that lasted from 2002 to 2017, when she worked at
Dover College in Kent. Seymour then worked as head of the Senior College at
Queen's College, London, mentoring students through applications for university. She was an associate professor at the
Open University in both the Music and English Literature departments from 2006, conducting Summer music classes and was a tutor at the
Rose Bruford College on its postgraduate opera studies course. She was also head of postgraduate studies at the
London Contemporary Dance School. In 2008, Seymour joined
Opera Today as a reviewer, and became the magazine's British editor in 2012. She also wrote for other music websites and publications such as
Seen and Heard International,
MusicWeb International,
British Theatre Guide and
The Stage. She published the thesis
The Operas of Benjamin Britten: Expression and Evasion that analyses all of Britten's operas in 2004. Seymour was a specialist on
Thomas Hardy and was a contributor and later editor of
The Thomas Hardy Society Journals from 2005 to 2009. She edited Wordsworth editions of Hardy and
Henry James as well as Plumbago’s Defining Opera series and authored programme articles for Glyndebourne and Wexford. Seymour had appeared on
Music Matters on
BBC Radio 3. She was also a semi-professional violinist. Seymour was part of the Oare String Orchestra for 28 years and was a member of both the Kent Concert Orchestra and the Peycelon Quartet. She frequently accompanied choral societies, performing with the
Lambeth Orchestra. ==Personal life==