There is this entry for a death in Victoria, Australia in 1924:
William CALVERT age 71
Birth year: 1853
Death year: 1924
Father's name: Calvert John
Mother's name: Jane Coulson
Death place: Bdale ( ? Bairnsdale)
Registration No: 7958
But there is also a marriage entry for "William Coulson CALVERT to Mary WHITE" in 1874 in Tasmania (registered in Victoria #3978.)
I have not been able to locate a marriage in Victorian records for your William to Mary Ann Smethurst. You have not included a year in the above details.
Which state were their children born ?