Rhondda started her interest in conducting children’s choirs and her love of music with children through the production of 
many musicals in both Girls Brigade, Mt Roskill Baptist and the Church children’s choir.
When she was asked to take over the Mt Roskill Youth Choir in the early 1990’s Rhondda had very limited knowledge of conducting, vocal pedagogy, or what was suitable music for children so she decided to attend every workshop available to learn the art of choral conducting. She has attended many International Summer Schools for Choral Conducting, local workshops, became a member of the Association of Choral Conductors attending their conferences, had voice lessons all to assist her to become an effective conductor. Singing in Auckland Choral has also contributed to her understanding of the singing voice and what is involved in singing in the choir. And so her passion to bring choral singing to all children who wanted to sing grew.
She developed the Mt Roskill Children’s choir to be for any child 5 years & over who wanted to sing. Renamed The Auckland Children and Youth Chorus the choir consisted of three all comers choirs for 5-7 year olds (Junior Choir) 8 – 12yr olds (Senior Choir) and the Chamber Choir for 13 years and over. Entering her choirs in the NZCF Kids Sing and the NZCF Big Sing also contributed to her development as a choral conductor.
Dame Sister Mary Leo Niccol DBE was a New Zealand religious sister who is best known for training some of the world's finest sopranos, including Dames Malvina Major, Kiri Te Kanawa, and Heather Begg.
She was born as Kathleen Agnes Niccol in Auckland and educated by the Sisters of Mercy. She had a talent for music and eventually adopted the vocation of a teacher of music. She took private classes in dancing, elocution, and singing.
She joined the Sisters of Mercy at the age of 28, taking the religious name Sister Mary Leo. She occupied herself in the work of her religious institute in tending to the sick and needy. Sister Mary Leo initially began her teaching career as a violin teacher. She never received formal training in vocal technique. It was in the late 1930s, after she heard a recording of Deanna Durbin and was so taken with Durbin's natural tone, flexible technique, vocal range, and repertoire that included both opera and light music, that she decided to devote her time to teaching singing.
She developed the already strong musical tradition of St Mary's College in Auckland, with its orchestra, choirs, and individual tuition, and also conducted the Sisters' Choir. From 1934, the college offered private tuition, and her reputation as a vocal coach flourished.
From 1950 on, honours and plaudits followed the success of such students as Dame Malvina Major, Dame Kiri Te Kanawa, Dame Heather Begg, Mina Foley, Judith Edwards, Elisabeth Hellawell, Patricia Price, Mona Ross and Elaine Dow.
In 1980 the Grand Opera Society of Auckland established the Dame Sister Mary Leo Scholarship in her honour. She was appointed a Member of the Order of the British Empire, for services to music, in the 1963 New Year Honours, and elevated to Dame Commander of the Order of the British Empire in the 1973 Queen's Birthday Honours. She died in 1989, aged 94.