Jean Denise Theobald was born on 7 October 1919, the daughter of Eleanora and Frederick. She married Rev Guy Wyndham Sich in 1941 in Barnstaple, Devon. They had three children during their marriage. She died on 4 June 1979 at the age of 59.

Almost certainly the illegitimate daughter of Frederick Hamilton-Temple-Blackwood, 3rd Marquess of Dufferin and Ava (Uncle Freddy). He died in an aircraft crash in 1930.

Her sister, Margaret, married an Austrian Catholic, Hans Welser, and the marriage service was conducted by Fr Guy Sich,who was an Assistant priest at Our Lady of Victories, Kensington Church St. This was the first time Jean met Guy Sich. She subsequently sought instruction from him prior to converting to Roman Catholicism herself. They continued to meet, fell in love and married in a registry office in Barnstaple, which led to the excommunication of Guy.