She was also a prominent spiritualist. An active philanthropist, Sandhurst ran her own home for sick children in the Marylebone Road. In January 1889, Lady Sandhurst was elected to the London City Council at the head of the poll.
However, because she was a woman, one of the defeated candidates, the Conservative Beresford Hope, petitioned against her election, and both the Court of Queen"s Bench and the Court of Appeal ruled against her.
Sandhurt"s seat was given to Beresford Hope in May 1889, and Sandhurst was fined £5 for every vote she had given during her tenure on the council. As a result of what was regarded by many as ill-treatment of a democratically elected candidate, and in recognition of her sympathy towards Ireland, in September 1889, Sandhurst was awarded the Freedom of the City of Dublin.
In 1890, she was elected president of the Society for Promoting the Return of Women as County Councillors. Sandhurst wrote at least two pamphlets on her political interests, one of which, Conversations on Political Principles, was published by the Women"s Liberal Federation.
Her descendants include the later Lord Sandhursts and the present Earl of Macclesfield.