Dudley was born in Beckenham, Kent. She graduated with a master's in music from King's College London in 1978. Trained as a classical performer, she moved into the competitive commercial field as a session musician, where her professional relationship with Trevor Horn began. In 1982 Dudley made significant contributions to the Horn-produced "The Lexicon of Love" album by ABC. She went from fleshing-out keyboard parts to scoring the album's orchestrations (which were, according to Horn, her first-ever string arrangements) and also co-writing some of the songs. In 2019 she conducted the Southbank Sinfonia during Martin Fry's Lexicon of Love tour.