For information - and to get things in order in my head, and because I suspect you do not have the original images. I have linked to them. (You have to create an account on Familysearch, but there are no fees) There is quite a lot of other information to be gleaned.
This is the sequence I see from James Henry RUDMAN
James Henry RUDMAN m Mary Elizabeth THOMSON
James RUDMAN m Mary BUCKLEY
Samuel RUDMAN m Ann TRINGHAM
John RUDMAN m Elizabeth ELLEN
Jeremiah RUDMAN m Mary GIBSON
Nicholas RUDMAN m Sarah HELPS
All events South Africa James Henry RUDMAN m Mary Elizabeth THOMPSON 8 December 1875
https://www.rootschat.com/links/01tf9/ his death registration in 1902 confirms birth about 1847, Cape Colony. Parents
James RUDMAN and
Mary BUCKLEY Informant is a son.
https://www.rootschat.com/links/01tf7/__________________________________
James RUDMAN & Mary BUCKLEY married 1847 (not Henry & not Elizabeth)
a witness who makes her mark is Martha RUDMAN
https://www.rootschat.com/links/01tfa/James death reg (1884) names his parents as Samuel & Ann RUDMAN
He is 62 years old so born about 1822 Cape Colony.
https://www.rootschat.com/links/01tf8/_________________________________
Samuel RUDMAN & Ann TRINGHAM
I cannot see Samuel’s death supposedly 1July 1841 - but no-one has a source for that.
A child - Rachel Eliza was born & baptised 1840
Now we are in EnglandMarriage St Andrew, Holborn, City of London
Samuel RUDMAN & Ann TRINGHAM married 12 December 1819. image on Ancestry
both signed
a witness was Benjamin RUDMAN. Brother? Also went to South Africa?
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England & Wales Non-Conformist and Non-Parochial registers - Ancestry
“ The children of John Rudman. Himself was born Jan 27th 1765
whose wife was Elizabeth the Daughter of Thos Ellen
(his wife is a member)
James Rudman was born the 19th of Sept 1788
Samuel 16th Mar 1790
Rachel 10th July 1791
William 24th Dec 1792 died in infancy
Benjamin 9th Apr 1794
Hannah 24th July 1796
Jonah 15th May 1798
Martha 4th Aug 1800
Mara 9th May 1802
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John RUDMAN of this parish (St Mary the Virgin, Devizes) married Elizabeth ELLEN of the Chapelry of St James Bishop Cannings. 3rd Banns 7th October 1787
Baptism 2 February 1765 at Rowde, Wiltshire
John RUDMAN, son of Jeremiah RUDMAN and Mary
would fit with non-parochial details above
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a marriageJeremiah RUDMAN (of this parish) and Mary GIBSON (sojourner) married by banns 7th July 1758. a witness is M(?) RUDMAN
a baptism28 Feb 1734, (birth 23 Feb 1734) Rowde, Wiltshire, Jeremiah. Parents Nicholas RUDMAN & Sarah
So
if that is the correct path back
perhaps this marriage
Nicholas RUDMAN & Sarah HELPS 20th June 1725 at Rowde.