Terry, I think your mother's career is very cool. I love the ATS ladies who were attached to the RA AA Batteries. You might enjoy watching the war time made movie "The Gentle Sex", which is about 7 ATS girls, some of whom were in an AA battery.
https://www.youtube.com/watch?v=UTs1kUgV6H0
Do you know what your mother's duties were in the battery?
Would love to see the picture if you wouldn't mind sharing it.
Terry