https://recordsearch.naa.gov.au/ is sometimes a useful place to search for Australian records.
They have a WW1 army file for John Andrew McGregor.

Search for:
McGregor John Andrew N90004

Image 32 says his father is Andrew Walter and mother Mary O'Loughlin, born 10 August 1899.
Sister is Mary Armstrong.

There is information there about the desertion and a plea from his mother.

Thanks Terry I do have all that info.
Lyn