Barry,
If you were to download (link at end of message) the Birth Certificate for the youngest child of Thomas Knight and Margaret Jones - all their children should be recorded on it.
Details for their youngest child;
Arthur Henry Knight - born 1876 - reg number 23438 - Goornang.
https://online.justice.vic.gov.au/bdm/homeAlso you could purchase the Death certificates for Thomas & Margaret Knight - however I think I would get Arthur Henry's first.
Thomas Knight - died 1905 (age 73) - reg number 1804 - Goornong -
parents - Richard Knight - Ann Porter.
Margaret Knight - died 1919 (age 86) - reg number 17413 - Goornong -
parents - Edward Chaplin Jones - Elizabeth Williams.
EDIT - Who were the Witness to the Marriage of Matilda Knight and Alex Ferguson??
Sarra