Marguerite de Beaumont

Marguerite de Beaumont was the author of one of the best known biographies of Lord Baden-Powell, the founder of Scouting, "The Wolf That Never Sleeps".
With her younger sister Elizabeth, Nesta Maude, and Rotha Lintorn-Orman, she was one of the girls who showed up at the 1909 Crystal Palace Scout Rally wanting to be Scouts, which led to the foundation of the Girl Guides. The Crystal Palace was an enormous exhibition facility and stadium in London, and housed the first large gathering of Scouts, the forerunner to all later Jamborees, in September 1909. The Rally included displays, contests, a march-by of all the Scouts, and an inspection of the troops by the Chief Scout. At the end of the march-by, the last Scout patrol in a group of 11,000 consisted of nine girls, wearing Stetsons and carrying Scout staves. B.-P. approached the girls and asked who they were. "We're the Girl Scouts," to which he replied "You can't be; there aren't any Girl Scouts." 16 year old Nesta retorted swiftly "Oh, yes there are, 'cos we're them!" This was the Wolf Patrol, led by Marguerite as patrol leader and her younger sister Elizabeth. In 1908 they had registered as a Scout troop, using their initials rather than forenames. Also at the Rally were a group of girls calling themselves Pinkney's Green Scouts, and two representatives from the Girls' Emergency Corps. These three small groups of girls at the Crystal Palace Rally are often cited as the origin of the Girl Guide movement.
Marguerite went on to become close personal friends with the Baden-Powell family, a Scoutmaster and Girl Guide Commissioner.
Birth.
She was born probably in the first quarter of 1899, in Barton upon Irwell, Lancashire, to Thomas Beaumont and his wife, Elizabeth nee Hartley, who were married there in the second quarter of 1892..
B-P's Diary.
B-P mentions in his diary, on 11 Oct 1918, regarding a visit to the "Scout Hut" at Etaples. 
On 22 Nov 1922 he wrote, "Mrs [Miss?] E (Elizabeth) de Beaumont came to stay. (1908 Girl Scout ) " - that would probably be Marguerite's mother - or sister.