Re John Lamb;
As burial does not have an age we are only guessing when he was born.
So a range of 1721-1750 is possible.
Also we have no idea if he was actually born in Durham.
But I am going to go with what I have found.
A JAMES Lamb was bapt children Stockton-on-Tees;
DOROTHY 27 Sep 1750
MARGARET 30 Jul 1752
Father JAMES, Mr James Lamb
ELIZABETH 16 May 1755, Parents JAMES/DOROTHY, Mr James Lamb
DOROTHY, Wife of JAMES Lamb, Wine merchant, buried 26 Dec 1791
Dorothy (1750) died 1835 unmarried and her Will is on Ancestry.
I am unable to read it properly.
(waiting for an eye op!)
Also Margaret died 1839 age 86
Cant see a Marriage for James Lamb to a Dorothy but was hoping for one to see if they had a John born pre 1750!