Carol,
Preston in the north of the county lay within the Parish of Ellingham and for BMD registration purposes, under the jurisdiction of Belford Registration District Office, as emjay suggested, seven miles away.
There is also a Preston in the south of the county, now within the conurbation of North Shields/Tynemouth.
Then, Preston lay within the Parish of Tynemouth and within the area of Tynemouth Registration Office ( although the sub-district office at North Shields was nearer for registrations)
And for any of your folk who wandered over the border into Scotland, there was/is a Preston, near Duns, in Berwickshire ( Now "Borders" )
Michael Dixon