The following are from Queensland Australia records.
Margaret married James in 1886. They had 3 children between 1888 and 1895.
From 1897 to 1907 Margaret registered 4 more children. There was no father recorded. In 1930, Francis completed 4 amendment to birth forms, listing himself as father to the 4 children.
There are no notes on the birth form or registry entry prior to 1930 with a mention of Francis or his surname.
I have talked to one of the researchers at Queensland Birth Deaths and Marriages. No field was available for preferred surname of child on the birth forms for the period concerned. I was advised if a father was recorded, the children would have his surname. If no father was recorded, the children would have been Margaret's married surname.
I have not located any student record for the children. Electoral rolls show the children using Francis's surname from their respective first available roll.
James died in 1935 and Margaret and Francis married later in 1935.
What records might I be able to pursue to find if the children used Francis's surname from birth or began using it later.