Hi Deb,
Hope this will help. Checked a few data bases for your spelling of GARNAUT. There doesn't appearto be any occurences of the name on 1841 thru to 1901 Census for UK or Channel Islands.
The only ref 's are in BMDS in WALES during 1800,s.,
Marriage Thomas Garnaut 1837 Jul-Aug-Sep Swansea Glamorgan, West Glamorgan
Birth. Ph_Be Garnaut 1848 Oct-Nov-Dec Swansea Glamorgan, West Glamorgan
This would suggest Welsh not English roots for you.
On the uk 192 and Elect reg for recent years there is only one listed.
Marriage of Alexis C Garnaut to

? Stannard , Nov 2004 Hackney London
There are 2 mentions of Charles Garnaut on Ancestry World trees.
Charles Louis 1889
F: Giles Gudge Garnaut
M: Ruth Duffield
Charles Louis 17 OCT 1889
Rosewater, South Australia.
F: Giles Budge GARNAUT
M: Ruth DUFFIELD
Presume one entry could be your own tree!
Good Luck with your search and Merry Christmas. Roger.