Cadet Uniform Buttons
Church of England Grammar School Cadets

Backmark: A. J. Parkes Brisbane 1929-1952

The Queenslander, 1st September 1932 page 4.
The Anglican Church Grammar School (known as the Church of England Grammar School until 1984), was founded in 1912 as St Magnus Hall in Toowong. It relocated to East Brisbane in 1918. The crossed axes on the button symbolise Viking courage, and relate to the school’s patron saint, St Magnis, who was a Norseman.
The cadets corps of the school formed as part of D Company, 5th Battalion Australian Military Forces in 1919. After the suspension of compulsory cadet training by the Government in 1929 the school decided to continue none-the-less, its cadets becoming the Church of England Grammar School Cadet Corps.

The Brisbane Courier, 26th November 1930 page 16.

The Telegraph (Brisbane), 13th May 1939 page 14.
Many former cadets enlisted during both World Wars. In 1948 it was claimed to be the largest cadet corps in Australia.
https://en.wikipedia.org/wiki/Anglican_Church_Grammar_School
Cadet Corps have existed in Australia since 1865. See http://www.austbuttonhistory.com/uniform-buttons-2/school-buttons/
The first official review of Victorian school cadets took place in 1885:

The Argus (Melbourne), 5th December 1885 page 13.
An article about the senior cadet (above 15 years) movement in Melbourne in 1888 follows:

The Age (Melbourne), 14th January 1888 p10.

The Victorian Volunteer Cadets were formerly gazetted in January 1885. In the above article it appears that the button had not yet been designed in January 1888.