Dorothey family name aka Doherty from County Clare

I have a Sarah with surname above born c. 1837 in Ireland.  I have found shipping record of her migration to Western Australia in 1856 as an 18year old occupation servant. 

On her marriage certificate in 1857 to William Hills in same state of Western Australia she states her fathers name is James Doherty occupation Boot/Shoemaker.

Her childrens records show her surname as the following:

Variations on surname spelling for all children. 

1st born - Sarah Emily Hill, mothers name Sarah 'Dorathy'
2nd - Annie Hill, mothers name Hill
3rd - Alice Hill, mothers name 'Dorathy'
4th - Betsy Hill, mothers name 'Doherty' and first name Sarah Ann
5th - Hannah Hill, mothers name 'Dorrittey'                                                                 5 births surname spelled "Dorathy"
6th - Harriet Hill, mothers name 'Dorothy'                                                                   All births bar one mothers name is only "Sarah"
7th - Mary Ann Hill, mothers name 'Dorathy'
8th - William Thomas Hill, mothers name 'Dorathy'
9th - Fanny Jane Hill, mothers name 'Duffity'
10th - Frederick George Hill, mothers name 'Doethy'
11th - Sarah May Hill, mothers name 'Dorathy'

I have been unable to find any link in Ireland for her and am hoping that someone may be able to help.

Thank you for viewing and I am hoping being able to help.

Cathryn