She was home-schooled and studied piano under Angus Morrison, harmony with Herbert Howells and violin with W. H. Reed at the Royal College of Music.

[1] Dyson began playing the clavichord and harpischord at the home of the musicologist Susi Jeans, and brought a Robert Goble-made harpsichord.

[2] She made her debut on the piano at Wigmore Hall with the London Women's String Orchestra on 15 November 1941.

[1] During the Second World War, Dyson did auxiliary nursing at Dorking General Hospital for the Red Cross, taught music to evacuated children at Dorking's War Evacuation Day Nursery, and toured in factories, hospitals and military camps.

Dyson undertook tours of Europe with sponsorship with the British Council and frequently broadcast on the BBC for more than three decades, several of which were the maiden performances of works by contemporary artists for early keyboard instruments.

[4] Some of her students included Carol Cooper,[5] Penny Cave, Melvyn Tan, Robert Woolley and Sophie Yates among others.

[6] She taught in fluent German at Hamburg's Telemann Society in 1963 and in French to the harpsichord world forum in Paris in 1976.

[6] Dyson married the joint intelligence bureau research officer Edward Eastaway Thomas on 2 May 1964.

[1] According to Margaret Campbell in The Independent, Dyson was "charming, unaffected and modest despite the fact that she had an incredibly scholarly mind" and generous towards fellow musicians.