I know that George Henry WIGLEY was not born in Victoria. I gave you this information -
FreeBDM SepQ 1858 W Ham 4a / 19
WIGLEY Georg m. CROSS Mireumn
Can you be specific about your confusion ...what are you confused about?
If it is about occupations, you need to consider context.
......Information given by the person....self reporting.
....information given about the person, during their lifetime, by another person.
....information given about the person after their death.
George Henry WIGLEY jnr, as informant for the death certificate of his father, George Henry WIGLEY snr, and describing the paternal grandfather that he would have no memory of, is likely using information gained about family generally - someone among his WIGLEY / CROSS ancestors was a competent healer of ailments in animals. Consider it to be useful information in researching your WIGLEY / CROSS ancestors.
I do not think there is much point to pursue the matter of John WIGLEY being a veterinary surgeon.
You might like to identify other children of John WIGLEY and Harriett PORTER, siblings of your George Henry WIGLEY, to see how they describe occupation of father John WIGLEY on their marriage records.
Birth certificates of children born to George WIGLEY and Miriam CROSS in Victoria would ask for father's occupation. For all that George, in NSW, is an instrument maker, I think his occupation in Victoria would be something else. The 1866 birth is closest to the 1861 Census in England, and information might be useful to locate the WIGLEY family in this census.
BDM VIC births
1866 / 16547 WIGLEY Alfred Robert parents George Henry / Miriam (Cross) @ CARLTON
1868 / 17648 WIGLEY Ellen Harriet parents George Henry / Miriam (Cross) @ MELB
1870 / 17147 WIGLEY Henry Edward parents George Henry / Miriam (Cross) @ MELBOURNE
From the death certificate, George Henry WIGLEY, and attached to family tree on Ancestry -
Informant: George WIGLEY, son, 42 Albert St Stanmore
George Henry WIGLEY, surgical instrument maker, 65yrs, died 2 Oxford Sq 18 Dec 1901
Father: John WIGLEY, veterinary surgeon
Mother: Harriett PORTER
Married: London England at age 22yrs to Miriam CROSS
Born: Birmingham England, 29 years in NSW, 6 years in VIC
Issue: George H 42y, Walter J 40y, Miriam A (JACK) 38y, Ellen (LEECE) 34Y living
4 males deceased
Buried: 20 Dec Independent Cemetery Rookwood.
This would be the four sons, deceased at 1901 -
BDM VIC death
1867 / 1146 WIGLEY Alfred parents George / Miriam (Cross) age 4 @ CARL
1870 / 9499 WIGLEY Henry parents George / Miriam (Cross) age 5 @ CARL
BDM NSW death
1875 / 849 WIGLEY Herbert parents George / Miriam @ Sydney
1873 / 633 WIGLEY Edward A parents George / Marion @ Sydney
At Rookwood Independent Cemetery
George H WIGLEY 87 Year 2/06/1971 Zone A /Independent General F 80
George Henry WIGLEY 91 Year 27/06/1950 Zone A /Independent General F 80