Tazz,
Just adding a wee snippet to all the info Pels has supplied...
The renowned glassworks at Seaton Sluice belonged to Lord then Lady Delaval. It was earlier Delavals who "cut" the sluice to give the Seaton Burn two outlets to the sea... and a deeper harbour to facilitate their exports of glass and coal.
In a hierarchy of places of the day, Seaton Sluice ( called Hartley Haven in pre-"sluice" days) lay within the "township" of Hartley, which was one of the eight "townships" that made up the Parish of Earsdon.
Go to web site communities.northumberland.gov.uk .. look in the "Seaton Sluice" community to see old photos,including some of the glassworks, maps, history and much more.
Michael Dixon
Newcastle