the registration district of Crickhowell covered these parishes
https://www.ukbmd.org.uk/reg/districts/crickhowell.htmlVaynor not included, it was covered by Merthyr Tydfil
https://www.ukbmd.org.uk/reg/districts/merthyr%20tydfil.htmlIf you use the GRO site to check for registrations, you get mother's maiden name as well which can help to eliminate candidates.
https://www.gro.gov.uk/gro/content/certificates/default.aspThe maiden name given for that birth reg is Bishop and there's also a Stephen Joseph with same mmn registered 2 years earlier leading to this family in 1901
25 The Rise, Beaufort RG13/5172 folio 49 pg 4
Evan Thomas head mar 32 miners secretary's clerk
Mary Jane wife 30
John Edgar son 9
Stephen Joseph son 7
Annie dau 5
Harold son 1
Fanny Williams mother-in-law widow 70 b. Somerset, Paulton
all born Beaufort except Fanny
Evan Thomas married Mary Jane Bishop dec qtr 1890 Crickhowell vol 11b pg 259
If she was born in Vaynor, Annie Ellen should have been registered at Merthyr Tydfil. There is
Ellen dec qtr 1897 mmn Davies vol 11a pg 732
Ellen march qtr 1895 mmn Phelps vol 11a pg 742
Eleanor Ann march qtr 1898 mmn Williams vol 11a pg 700
Annie dec qtr 1896 mmn Holmes vol 11a pg 775
Ann march qtr 1896 mmn Davies vol 11a pg 716
Ann dec qtr 1895 mmn Thomas vol 11a pg 644
Ann dec qtr 1895 mmn Jones vol 11a pg 672
Ann dec qtr 1895 mmn Lewis vol 11a pg 638
Ann march qtr 1896 mmn Davies vol 11a pg 716
Ann march qtr 1898 mmn Thomas vol 11a pg 737
So you may need to ask the registrars to search to check names of parents
https://www.merthyr.gov.uk/resident/births-deaths-marriages/copy-certificates/