Georgina and Pauline Rawdon-Smith may have been models for Nancy and Peggy. Christina Hardyment has a photo of the two young girls in swimming or holiday costumes outside a low building or shelter, and says that they used to wear shorts (unusual for girls then) and looked tomboyish in early photos of them. With their brother Rawdon they visited a cousin Miss Holt at Tent Lodge near Lanehead. However she was not convinced that the vivid character of Nancy was based on such a casual acquaintance (CFT pp 70,100 & photo 8).
The Rawdon-Smiths met the Altounyans, and Pauline met Arthur once. They may have been the two girls in red caps that Arthur saw once by the side of the lake (NBUS p. 21)