Hi
NSW BDM are online and free to search at
http://www.bdm.nsw.gov.au/familyHistory/searchHistoricalReco...I have find the birth of William registered in 1860
4159/1860 RUMNEY WILLIAM A father THOMAS mother HARRIET N district ST LEONARDS
and the twins as follows registered in 1862 (note the spellings are as the appear)
3959/1862 RUMLEY HENRY C father THOMAS mother HARRIETT District ST LEONARDS
3960/1862 RUMLEY GEORGE T father THOMAS mother HARRIETT District ST LEONARDS
You can also purchase the certificate online or for a cheaper option hire a transcription agent, see
http://www.bdm.nsw.gov.au/familyHistory/howToSearch.htm#Tran...Regards
Ina