I've come across a couple, James and Mary Ann McKenna (nee Newton), who are on census records as a married couple between 1861 and 1891 in Sunderland. Mary Ann was born in 1837, James seems to have been born in 1832 (based on the 1851, 1881 and 1891 censuses), though his age is listed, probably mistakenly, as '26' in 1861. The census consistently has James down as an Iron worker for occupation.
These are their children listed in 1871:
Isabella McKenna, age 16
John McKenna, age 14
Jane McKenna, 7
James McKenna, 5
Ralph McKenna, 2
Their children appear on the GRO with the surname rendered variously as 'McKenney', 'McKenna' and 'McKanna', that kind of spelling variation is to be expected. Nevertheless, the MMN is consistently "Newton".
The most likely candidate for the Mary is a Mary Ann Newton, aged 13, on the 1851 Census, daughter of Robert, 49, and Hannah, 47.
James seems to be listed in 1851 aged 19 as the son of a Mary McKenna (head), at Monkwearmouth Shore Sunderland.
The marriage therefore took place between 1851 and 1861, but I can't find a marriage between these two names between those dates in Sunderland, or Co Durham in general. Their first child Isabella was born in 1854, so around then is a possible date. Any help her ould be greatly appreciated.