Raised in West Yorkshire, Farrell studied at King's College London, and the Guildhall School of Music.
A founding member of the St Thomas More Group, CHIME and the Music in Worship Foundation, she served on the Roman Catholic Bishops Liturgical Commission for many years.
On the staff at Allen Hall Seminary from 1980 to 1986, her work in adult education encouraged the formation of lay liturgical ministries.
[2] Writing in a variety of styles, Farrell draws inspiration from the English choral tradition as well as the melodic roots of British folk song.
She also sets to music the words of other authors, including those of her husband Owen Alstott, and New Zealand writer Shirley Murray.