May I commend x3 books to you all
Mud Blood And Poppycock by Gordon Corrigan
Forgotten Victory by Gary Sheffield
Blindfold And Alone by Hughes-Wilson and Corns
I'm afraid that there is a lot of myths around re WW1, and an awful lot of them perpetrated by things such as "Oh What A Lovely War" and several badly written and researched books.
All the shot at dawns were not deserters over 20 of them were convicted murderers, and received the punishment set by the civilian courts at the time.
And of all the allied armies, we executed the least apart from the Americans, and only a tiny percentage of those condemned were ever executed.
Psychiatry was in its infancy, and many, many were given psychiatric help...Pse see "Forgotten Lunatics Of The Great War" by Peter Barham
Trevor, perhaps you really need to read the above books...Officers did not sit well back from the front line....The amount of Generals KIA will surprise you!!