I believe he was also the person who first got P.D. Ouspensky published in English.
Edit: yes - he produced the first English translation of Ouspensky as early as 1919. Ouspensky was a refugee in Constantinople, had no idea the translation had come out, and Bradgon had no idea where he was. Eventually he found him and sent him a royalty check and this led to Ouspensky's emigrating to England.