There is a WW1 record for Thomas Sanders, living WA, b. Guildford, Vic...44 6/12 at Jan 1916....platelayer.
NOK wife Ellen, allowances to Walter James Sanders, Joseph Sanders and Winifred Sanders.
WW2 nominal roll has Joseph Sanders, b. 7 Mar 1909, Perth, WA, NOK Ellen Sanders, Clifton Hill, enlisted 20 Apr 1942.
WA BDM has Walter James Sanders b. 1904, Perth, parents Thomas James Sanders, Ellen Bourke.
WA BDM has Winifred Sanders b. 1907
So three other children to this couple 1904+ and you would expect a few more between 1896 for Janet, and 1904.