Jessy,
All Saints-Tynemouth-Longbenton... are THREE different places... although All Saints and Longbenton were neighbouring parishes, the former within Newcastle, the latter outside of Newcastle.
I hope this is not me teaching grannie to suck eggs, but I think you need to identify all the characteristics of your great grandfather and focus on these.
Is the Sowerby family living in Walker, Parish of Longbenton, on Census 1851
(page ref 2411-85-12) "yours" ?
Michael Dixon
Newcastle