Brought up in West Wittering, Mary was the daughter of Brigadier Hudleston Noel Hedworth Williamson and Leila Isabel Lodwick, a well-known author who wrote 12 novels and two biographies under the name Eve Orme.
She married Lord Nicholas Gordon Lennox, the younger son of the 9th Duke of Richmond, on January 15, 1958, and had four children, Sarah, Henrietta, Lucy and the late Anthony.
Mary died peacefully on September 26 at the age of 87 and the funeral service was held at Chichester Cathedral on October 11.
Henrietta Lindsell, her daughter, said: “We were able to have a full funeral at Chichester Cathedral, a very traditional funeral with 260 people. It was very fitting to my mother, who was a lady of great faith.”
Born Mary Williamson on March 20, 1934, she came to West Wittering at the age of four, when the family bought the property known as South Nore.
Henrietta said: “It is a very clear landmark, a pink house that commands a great position. She was effectively brought up as an only child, as her step-sister was a lot older.
“She was envious of larger families. Hence, she developed as a fiercely independent woman working for a living in the flower shop in the Dorchester before travelling out to New York.”
Mary was a very good pianist as a girl and often spoke of the music prizes she won at school. Her mother had been a talented amateur violinist and studied under Hindemith.
Henrietta said: “Although she had a poor education, she had a constant interest in politics and current affairs and was liberal by inclination.
“She was an energetic and brilliant letter writer and her letters home to both her parents and parents-in-law, which have been kept, chart her life from early married days right through her life abroad, describing amusing stories about family life and visiting dignitaries, and describe the culture and customs of the country she was living in.”
Mary went on to lead a glamorous life abroad but after her husband died at the age of 73 in October 2004, she returned to live permanently at South Nore.
Lord Lennox was raised at Goodwood House and the couple first met on a train travelling from Chichester to London. He was travelling with his mother and Mary had left her purse behind, so Nicky paid for her lunch.
Henrietta said: “She was very beautiful and modelled occasionally. She took her appearance and clothes seriously and had a keen eye for style. As a result, she was the picture of elegance and had a natural height, beauty and ageless appearance that made her stand out in a room.
“She was a very strong woman, very energetic, upright and very intelligent. She was very confident, very engaging, and very kind.
“She was married to a man in the diplomatic service, so she spent a lot of her time entertaining. She rushed through life at great speed and with great energy well into her 80s, when she developed pulmonary fibrosis. She only took to pause and reflect when her illness took over.
Mary loved the arts and at one time was involved with Chichester Festival Theatre, as well as being chairman of the friends at Pallant House Gallery.
She was also known for her hard work supporting St Wilfrid’s Hospice, serving as the chairman of the friends and as president.
Mary was Lady in Waiting to Princess Alexandra and was awarded two medals by The Queen for her work, including in 2018, as part of the Queen’s birthday celebrations, being appointed to the Royal Victorian Order.