In 1929 Plumpton reached the quarter-finals of the Girls Amateur Championship at Stoke Poges, losing to Joan Mitchell at the 20th hole.

[6] In the 1932 Women's Amateur Championship, Plumpton finished tied for 4th place in the qualifying but lost to Clem Montgomery in the second round.

[15] She played for the British team in the Vagliano Trophy match, against France, at St George's Hill Golf Club in late June.

[20] In July, Plumpton was selected for the British team to play in the Curtis Cup at Chevy Chase, Maryland.

[22][23] In the 1935 Women's Home Internationals at Royal County Down, Scotland regained the trophy, as they had done in 1927 and 1931, when it had previously been held in Ireland.

[27] In the 1936 Women's Amateur Championship she qualified but met Pam Barton in the first round, losing by one hole.

[29][30] In October 1936, she married Noel John Barrington Sabine, of the Kenya Administrative Service, in Nairobi.