Her third husband,
Alexander Keiller, had used wealth from his family's marmalade business to pursue interests in archaeology, particularly the stone circles at
Avebury in Wiltshire and the surrounding prehistoric landscape. He bought land to ensure the preservation of the monuments, and in 1938 created a museum at Avebury. After his death in 1955, Gabrielle employed
Isobel Smith to make archival records of Alexander's excavations in the 1920s and 1930s. Gabrielle gave the contents of the museum to the nation in 1966, after which it was named the
Alexander Keiller Museum. From 1956 to approximately 1970, she assisted
Rupert Bruce-Mitford in a study of the burial ship
Sutton Hoo, taking photographs of the site. == Personal life ==