Second Officer Kethleen Kershaw, ATA Casualty

[Tonym]

I note from the details that I have of Kathleen Kershaw that she volunteered for the flight with Captain Fairweather as a nursing attendant for the casualty they were due to pick up, she is described as a Nursing Sister.
Does anybody have any details as to whether she was a civilian trained nurse who joined the ATA or a Princess Mary’s RAF Nurse seconded to the ATA?
Any info most welcome

Tony