First of all I must apologise for the long delay in replying. It was only just recently that I gone into the site. Up until now, you are the only one to respond and I appreciate that. You mention dead ends well I am real in the same position as you in that I still cannot make progress in finding Sarah's parents. However, I can tell you that Charles Scott (born abt 1837 was the brother of John (born abt 1825). They had other brothers and sisters. Their parents were Robert Dodds Scott born abt. 1803 in Ancrum, Roxburgshire and died 11 March 1873 in Nelson, and Dinah Edwards born abt. 1802 Merthyr Tydfil and who died 28 Feb 1888.
John and Sarah married on 2 October 1842 at Ynysgau Chapel, Merthyr, His father Robert Scott was alive and so was her father William Jones (a butcher). They too had a large family: Charles, age 12 in 1861, George, Henry, Mary Dinah, and William. I can't find her father anywhere but he was certainly in Merthyr when they got married. It is a possibility that he lived in the area and was a travelling butcher or had a stall in the market place in Merthyr - the latter is more of a possibility.
As you probably already know both the Rees and Scott families were mainly licensed victuallers. The Rees family mainly in Merthyr and the Scott families in both Merthyr and surrounding areas.
I could never understand why her birthplace was given on the census
as Trallong and Llanwrtydd - may'be boundary changes on which I am not very knowledgeable. I did google up these places and I must admit Trallong looks interesting! It further intrigues me that William Rees married Sarah in Builth.
On other thing: I managed to track through Batch numbers and the IGI the following:
There is a birth recorded of a Sarah Jones on 27 August 1822 and a christening on 13 September 1822 at Aber Llanvigan (Llanfeigan?)Independent Chapel, Llanfeigan Brecon. The parents were William Jones and Mary Jones. I have not yet followed this up.
Perhaps you have quite a lot of the information as above but it seems to me that you and I and quite a few others are stuck on Sarah's parentage.
If you manage to find out anything, meantime, please let me know. It looks as if you and I have met up with the same brick walls. Gosh! there must be someone out there who will know the answer!
Once again I apologise for not getting back to you sooner.
Regards