Complex sentence: She first came to the attention of the Special Operations Executive when Harry Sporborg, a senior SOE staff member, saw her file and requested that she be appointed his secretary, but having already joined the WAAF, she began military training instead.
Split into simpler sentences: She first came to the attention of the Special Operations Executive when Harry Sporborg, a senior SOE staff member, saw her file and requested that she be appointed his secretary. Having already joined the WAAF, she began military training instead.