My 2x Great Grandfather, George Bell was born in East Farleigh, Kent, England in 1817.
In 1837 he and his brother, James, emigrated to Australia as sailors on a convict ship.
George Bell married Sarah Sargent at Sutton Forest, New South Wales in 1844.
This couple settled in Picton, New South Wales, and had a family.
Their children were all born in Picton, New South Wales.
George Bell Jr was born in 1845 and baptized in 1846.
James Bell was born in 1847.
Thomas Bell was born in 1849.
Harriet Bell was born in 1852
Henry Bell was born in 1854
According to the Bell family bible I have inherited, the next child was a son named John, who was born on 6 September 1856.
As this was the year Civil Registration began in New South Wales I checked for references in the online index of the Registrar of Births Deaths and Marriages in New South Wales in Sydney at https://bdm.nsw.gov.au/.
It should be noted that the date of the start of the registration of Births was 1 March 1856.
The search of this online index found that there was a reference to the baptism of John Bell, son of George and Sarah Bell, but no reference to a registration of a birth.
Remember the Registrar of Births, Deaths, and Marriages had called in the early baptism records prior to 1856 as State Records. These baptism records often had the birth and baptism date on those records.
Also note at this point in history it was up to the parents to make sure the child’s birth was registered with the registrar of Births, Deaths, and Marriages in New South Wales. In John Bell’s case, had his parents neglected to register this birth? The law only came in that year and not all families were conversant with this new law. Perhaps John was only baptized.
BELL JOHN, registration number 5955/1856 V18565955 121C, son of GEORGE and SARAH of IN
Using this reference I was able to search for entries in the Archives Authority of New South Wales (now State Records) Genealogical Kit (1988) for baptisms 1788-1855.
The early colonial baptism, marriage, and burial records of some 164 volumes cover the time before civil registration in New South Wales. This includes Victoria and Queensland which was part of New South Wales at that time. These are held as Government records by the Registrar of Births Deaths and Marriages for New South Wales in Sydney.
Many of these records were microfilmed and released to the public in the Archives Authority of New South Wales Genealogical Kit in 1988. Of the 164 volumes copied, only 123 volumes were released in the kit covering the time frame 1788-1855. Volumes 124-164 were not included in the kit.
This was because some of the records contained in the volumes were after 1855 so fell outside the parameters of the historical project and were subject to state privacy laws. Other volumes were not included because they were so fragile and the handling of those volumes would have destroyed them.
Returning to our Bell research, I found Volume 121 in the above-mentioned records, and I was able to view a microfilm copy of the original record on AO Reel 5046. [You will notice there is some crossover with baptism and birth registrations for 1856.]
Although you can view these records at your library you cannot make a printout as it is a condition of use of these records and is stated at the beginning of each film. The copyright belongs to the Registrar of Births Deaths and Marriages. I was able to make a transcription and add appropriate notes.
As parents were responsible for registering a birth from 1856, sometimes they just didn’t get around to it. In that case, you may not find the birth reference you were looking for. Another reason you may not find it is that you are not using the spelling which was used at the registration, or the child was registered without a Christian name, so it may be registered as an unnamed male or female.
This was the case in John’s birth registration.
BELL (MALE) Registration number 4010/1856 son of GEORGE and SARAH, registered at CAMDEN
I was then able to get his full birth certificate from the Registrar of Births, Deaths, and Marriages in Sydney using this reference.
This is my transcription of this document.
You will note the above mention baptism of John Bell was at the Wesleyan Church, Picton.
The Wesleyan Church, Picton
“On the 4th April 1849, the Colonial Secretary advised that the Governor of N.S.W. had given approval to allotments of land which had been granted to the Wesleyans in Picton on 4th January 1849. Shortly after, James Rogers began to build the chapel using convict labour. The original building was 26 feet by 16 feet, the stone being hewn from Stonequarry Creek. The roof was of shingles. The chapel was opened shortly after, in July 1849, but by 1865, because of the influx of population, especially railway men associated with terminal railway activities the little Wesleyan chapel was enlarged, again James Rogers carrying out the work: adding an extra 10 feet on to the back of the church. The early ministers who conducted services at the chapel were George Pickering (1849), J. Bowe (1852), J. Fillingham (1855), C.W. Rigg (1856), W. Clark (1859), S. Wilkinson (1861), J. Watkins (1864) and Richard Amos (1865). ” 
This church was not very far from the Bell home at Upper Picton, also known as Redbank.
I also checked in the newspapers to see if there was a birth notice or report but found none.
 Picton and District Historical and Family History Society Facebook page -Wesleyan Church
From <https://www.facebook.com/878976525498739/posts/redbank-uniting-church-picton-formerly-wesleyan-chapelon-the-4th-april-1849-the-/918616788201379/ downloaded by Nola Mackey, 3 September 2021