Hi Dave, Welcome to the forum, I had a quick look on the Mormon search program at 'Familysearch.org' for your family and found that Cuthberts father was John and there was also a Paul bpt 1725 and Isabella bpt 1722. Benjamin is recorded as 1766 at Aycliffe and another John in 1768 also at Aycliffe. Before 1733 the name Morson does not seem to appear in Bishop Auckland. Do you know if there is any evidence of a French connection?. Try all the variants you can think of, here are a few Mosson-Moson-Mawson-Moorson-Moorsom-Moreson-Morsom-Mossom-Manson-Morton-Mowson. There are Morson families both in Scotland and Yorkshire also around this time.
If you e-mail me direct at 'Mdmorson@aol.com' I will send you Jane Morson's address. she has indexed all the U.K. Births/Marriages/Deaths since 1837 and had constructed many Morson Trees from the Mormon records and other information.