5 Years War Service
Although the AE medal was awarded for 10 years service in the reserves, war service counted as double time. So a member of the then Aux Air Force or VR who served for 5 years in the war would have qualified.
Not all those reservists who served in WWII knew about this. I recently had the privelige of helping a WWII veteran claim his medal. He joined the Aux AF in April 1939 and was discharged in late 1945.
I believe it was only officers who could use the post nominal AE.
CC