13th Bde chap WW1?
 

Here's a rakish fellow, possibly 50th Bn AIF. I reckon he's back home in Aus and standing next to the ubiquitous rainwater tank. Just visible on the original photo is the inscription 'Cheers from Gordie'.

Did they discontinue those good conduct chevrons later in the war? Maybe he came home wounded?

Oz.

I'm afraid those chevrons are a source of endless mystery to me! They crop up on Australian uniforms in all sorts of guises. I leave it to those in the know to answer.