From an AbeBooks description
"Red Cross volunteer May Bradford knew better than most how important a letter could be. She was the official letter writer at the hospital which inspired the BBC s The Crimson Field No.26 General Hospital in Etaples, France. Throughout the war she wrote over 25,000 letters."

More information is in https://web.archive.org/web/20220707051753/https://www.independent.co.uk/news/world/world-history/history-of-the-first-world-war-in-100-moments/a-history-of-the-first-world-war-in-100-moments-the-soldier-and-the-letterwriter-a-lady-with-a-notepad-who-gave-comfort-to-the-dying-9474683.html

"A volunteer nurse for the British Red Cross, she followed her surgeon husband, Sir John Bradford, to northern France at the outbreak of the war and spent the duration of the conflict performing the remarkable yet unsung role of “hospital letter writer” for injured soldiers either too unwell or too illiterate to communicate with family members scattered across the globe".

There are some pages about the author in https://books.google.com/books?id=6KR2BQAAQBAJ&pg=PA27 page 27 We Also Served: The Forgotten Women of the First World War by Vivien Newman 2014