Hi Erika,
Given Thomas and Mary Ann's birth years they were not born in SA.
I see Mary Ann was previously married in Birmingham
Matthew
WILKES = Mary
NOTT Dec 1/4 1850 Birmingham
1851 Census
HO107/2057 Folio 399 Page 1
5 Price Street
Birmingham
WarwickshireWILKES Sarah Head 43 Widow b Darleston Staffordshire Employed at home
WILKES Matthew Son 23 Mar b Darleston File Maker
WILKES Mary Dau in Law 20 b Birmingham
WILKES Mary Ann Dau 16 b Birmingham Milliner
arrived Adelaide 11 Oct 1851 aboard the Christina
http://www.slsa.sa.gov.au/fh/passengerlists/1851Christina.gifBirths to Matthew WILKES and Mary Ann NOTT in SA
Sarah Ann 9 Oct 1851 Norwood Dist Ade 3 291
Mark 17 Jun 1853 Adelaide Dist Ade 4 167
Eliza Jane 22 Jun 1855 Adelaide Dist Ade 5 187
Harriet 6 Oct 1857 Adelaide Dist Ade 11 170
also a Charles died 24 Jul 1861 Adelaide Dist Ade 9 265 aged 16 Months Res Adelaide (Father Matthew) dont see a birth listed
Then there is
WILKES William Henry 29 Nov 1861 Adelaide Dist Ade Symbol S 20 235 Father Not Listed Mother Mary Ann WILKES nee NOTT
Presume this is because Matthew had died prior to the childs birth
Matthew
WILKES aged 33 died 27 Sep 1861 Adeliade Dist Ade 9 288 Res Adelaide
1841 Matthew is in Birmingham with his family - his parents are Mark and Sarah
BISA
WILKS Matthew b c1827 d 28 Sep 1861 Adelaide SA bd WTC arr 1851 CHRISTINA occ File Maker m unknown ch child
Mary Ann married John Frederick TURNER 28 Mar 1864
Children to John Frederick Turner and Mary Ann Nott
Marian 20 Feb 1865 Adelaide Dist Ade 33 184
James 19 Oct 1866 Adelaide Dist Ade 33 661
Joseph 27 Dec 1867 Adelaide Dist Ade 55 113
Laura Georgina 13 Sep 1870 Adelaide Dist Ade 87 397
Charles Todd 15 Nov 1872 Adelaide Dist Ade 115 377
Frank William 11 Mar 1874 Adelaide Dist Ade 113 135 (Parents John Frederick Turner and Amelia Ann Nott)
John Frederick
TURNER died 23 July 1892 Adelaide Dist Ade 203 428 aged 73 years res Adelaide Status rel not recorded
Mary Ann
TURNER Died 28 Jan 1895 Adelaide Dist Ade 224 337 aged 61 years res Adelaide Widow rel John Frederick Turner Deceased Husband.
Cheers Kris