This is a Memorial Plaque. These plaques were issued to the family of every soldier from the British Empire who died. Because of their size they were colloquially known as "Dead man’s pennies".
World War One was the bloodiest conflict in Europe for nearly three hundred years. In a little over four years, from July 1914 to November 1918, 10 million soldiers and 6 million civilians were killed. Sixty thousand Australians died, and more than were 150 000 wounded, out of a total force of 400 000 - nearly 10% of Australia’s population at the time.
This plaque was issued to the family of Leonard William Telford from Bendigo. Telford was killed in France in 1917 from a bomb dropped from a plane.
Like the Brunswick Town Hall Honour Board, the memorial plaques did not distinguish soldiers by their rank. All plaques were the same.