Seaton Sluice Harbour and Beach. Les Bell November 2, 2018 2018, Beaches, Blyth, Coast, Harbours, Lighthouses, Northumberland, Piers, Seaton Sluice These photos are from Seaton Sluice Harbour and include views of the beach and beyond to Blyth Lighthouse. Seaton Sluice Harbour. Seaton Sluice Harbour. Seaton Sluice Harbour and Beach. Seaton Sluice Harbour. Blyth Lightouse seen from Seaton Sluice using a very long lens – In the background are Newbiggin Bay and fuel silos at Lynemouth Power Station.