When she was a teenager Diana was sent back to England where she was educated at Manor House at Limpsfield, Surrey.
In 1933 Diana returned to France and enrolled at the Sorbonne. After completing the course she worked as a journalist in Paris. On the outbreak of the Second World War she joined the Red Cross and was assigned to the Anglo-American Ambulance Corps of the British Expeditionary Force (BEF).
In May 1940 France was invaded by the German Army. Diana was unable to join the evacuation at Dunkirk and remained in the country until the summer of 1941. After travelling through Spain and Portugal she arrived back in England where she was reunited with her mother.
In September, 1941, Diana joined the Women's Auxiliary Air Force (WAAF). Over the next year she worked at the Department of the Chief of Air Staff. In July 1942 she was promoted to Section Officer at Moreton-in-the-March.
Diana's ability to speak French fluently brought her to the attention of the Special Operations Executive (SOE). After being interviewed at the War Office in March 1943, she agreed to become a British special agent.
Given the codename "Paulette" she was flown to Le Mans with Noor Inayat Khan and Cecily Lefort on 16th June 1943. She travelled to St Amour where she joined the Acrobat Network led by John Starr. Over the next few months she worked as a courier delivering messages to agents in Marseilles, Lyon and Paris. She also helped Harry Ree in the plans to sabotage the Peugeot car plant.
On 18th November, 1943, Diana was arrested while with two other members of the French Resistance at Lons-le-Saunier. She was taken to Avenue Foch, the Gestapo headquarters, in Paris. After being interrogated for two weeks she was sent to Fresnes Prison.
On 13th May 1944 the Germans transported Diana and seven other SOE agents, Vera Leigh, Andrée Borrel, Sonya Olschanezky, Yolande Beekman, Eliane Plewman, Madeleine Damerment and Odette Sansom, to Nazi Germany.
On 6th July 1944, Diana along with Vera Leigh, Andrée Borrel and Sonya Olschanezky, were taken to the Concentration Camp at Natzweiler. Later that day they were injected with phenol and put in the crematorium furnace.