I come from a small place between Bergen and Stavanger and I have had my fair share of North Sea crossings on the ferry heading for North Shields. But to be honest VentureGo, Newcastle was never my end destination on the Isles - only a start point to explore the rest. Nowadays the ferry trips from the west coast of Norway have been replaced with flights mainly to London airports (SVG-LHR/LGW, HAU-STN and BGO-LHR/LGW).
VentureGo, if you insist on flying with Norwegian you have two airports they are are flying to within 2.5 hour drive from Newcatle - EDI and MAN - and since would flying against the flow I'm certain the ticket prices will be lower than what Widerĝe or SAS will try to charge you for at NCL.