 Girdlestone was appointed honorary canon of St Peter's Cathedral in 1912 by Bishop Thomas.He and his wife, with Archdeacon Hornabrook, put much effort and energy into the founding and running of St. Peter's College Mission, a charitable outreach at St. Mary Magdalene's Church, Moore Street off Angas Street.He was a member of the University of Adelaide council from 1901 and for most of his time in Adelaide actively involved with the Adelaide Rowing Club and its president 1913–15.