She won the British Open in 1961, defeating Ruth Turner in the final in straight sets 9–3, 9–5, 9–1.
[1][2] She also won the Scottish Open in 1962 beating Heather McKay in straight games, making her the last woman to defeat Heather McKay in squash.
[3][4] Marshall was raised in Kenya, and she represented Kenya in tennis at the Wimbledon Championships and was part of the Kenyan team at the 1981 Women's World Team Squash Championships.
[5] After marrying her husband, who was in the British Army, she moved to England and had lived there permanently since 1957.
This biographical article relating to a British squash figure is a stub.