Hallo Eeyore,
I don't know if you have had any help with your WOAS query.
Section 40 of the Army Act is a catch all section concerning "conduct prejudicial to good order and military discipline." The original charge sheet would have read "LCpl Eeyore is charged with conduct prejudicial to good order and military discipline while on active service in that he did on 18th April 1942................ " The dots of course are what interest you the most but it is most unlikely the original charge sheet would have been retained; simply the fact that he was charged and demoted. Here are some suggestions:
.......... was absent without leave.
......... was drunk on duty."
........... asleep at his post."
........... failed to report for duty when rostered."
It would not have been very serious because that would have led to a court martial but being demoted is not entirely trivial either, especially Woas.
Cheers urgr82