If Dazey is correct here is his death:
Thomas Young COTTER died 9.1.1882 aged 76 years. relative not recorded. Residence and Place of Death Port Augusta District : Frome. Book 116 Page 96
His wife:
Jane COTTER d 5.3.1876 aged 62 relative not recorded. Res & POD. Port Augusta 72/91
Children born to Thomas Young COTTER and Jane NICHOLSON all born Adelaide except Plummer who was born in Macclesfield
1. Ellen Fisher b 12.3.1838 Book 1 Page 5
2. Edward Gervais b 6.2.1840 1/5
3. Jane Mary b 3.9.1842 1/15
4. Plummer James b 2.10.1844 1/85
5. Henry Robert b 2.11.1848 2/96
6. Alfred John b 6.8.1850 3/87
7. Hurtle Richard b 7.6.1852 4/24 died 3.5.1853 2/208
8. Herbert Hallet b 14.8.1854 5/18
Marriages of children:
Edward Jervis COTTER 30 Single married Anna Maria SLEEP 27 Single on 5.12.1872 at Residence of Robert SLEEP Bugle Ranges 93/519
Plummer James COTTER 33 Single married Mary Elizabeth ANDERSON 27 Single on 16.10.1878 at Residence of Brides father Adelaide. Brides father: John ANDERSON 117/164
Jane Mary COTTER 22 Single married Frederich John FROST 34 Single on 13.12.1864 at unrecorded Nuccaleena District Frome Symbol A 60/368
Double wedding

Ellen Fisher COTTER 26 Not stated married James Bennett GIBBS 28 Not stated on 13.12.1864 at unrecorded Nuccaleena. Frome Sym: A 60/369
Julia Frances COTTER 24 Single married Thomas BURGOYNE 43 Divorced on 30.9.1871 at Residence of Thomas COTTER Port Augusta 88/745
Regards
Alison