was she also a director?
Yes, she joined Britten and Pears as one of the festival's artistic directors,
Imogen Holst
she joined Britten and Pears as one of the festival's artistic directors, 
who is imogen holst? A British composer, arranger, conductor, teacher, musicologist, and festival administrator. from where did he study? Royal College of Music which of his texts were published? Her numerous articles, pamphlets, essays, introductions and programme notes during the period 1935–1984. what did she do later in her life? She took legal action over a recording by Japanese electronic composer Isao Tomita of 'The Planets', calling it 'unworthy of my father's creation'.
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Imogen Holst [SEP] Artistic director
In 1956 Holst's role in the Aldeburgh Festival was formalised when she joined Britten and Pears as one of the festival's artistic directors, taking responsibility for programmes and performers. For the 1956 festival she scheduled a performance of Gustav Holst's opera "Savitri", the first of several Gustav Holst works that she introduced to the festival in the ensuing years. "Savitri" was offered as part of a double bill that included Imogen's arrangement of John Blow's 17th century opera "Venus and Adonis". In 1957 she instituted late-night concerts, and in 1962 she organised a series devoted to Flemish music, in which she had recently become interested.