Joan was selected for a commission during the summer of 1943 & commenced her training at Hardy House(another adjunct of HMCS Bytown) on July 25, 1943, she was rated as a Cadet Wren for her period of officer training. She was in Class IX(9).
Joan is third from the right second row, to the right of the very tall girl(her right) between the two rows:
Graduating class of Probationary Sub Lieutenants, WRCNS - Aug 14,1943.
I am not 100% certain exactly where Joan is in this blurry photo but think she is third row standing on the left:
