In 1966 Rosemary Sutcliff made a donation to the de Grummond Children’s Literature Collection at the University of Southern Mississippi in the USA. The Sutcliff Collection has a manuscript and two typescripts for the radio play The New Laird. (Taped in April 1966 and broadcast on 17 May 1966 as part of the BBC Radio Scotland series—Stories from Scottish History. The collection includes a red note-book of research for The Lantern Bearers, and for two unpublished works, The Amber Dolphin and The Red Dragon.
I have never found either published or unpublished the actual stories by those titles. What happened to them may be illuminated by her diaries, which are as yet unpublished. I have not read the notebook at the library.
However, The Amber Dolphin may have become The Capricorn Bracelet (1973). For an early paragraph begins: