Don’t forget NCL has also a wealthier part of its catchment area with the English Lakes not too far away as well as the Scottish Borders.
Many of my cousins chose NCL over EDI and one in particular loves EFL which was a few years back not available from Scotland.
As PiperOne will back me up NCL was always strong on Greece: EFL, JTR and JSI were all served by Thomas Cook and had the most northerly departures for these islands.
I well remember the BEA Airtours 707s serving Corfu for OlympicHolidays way back in 1973 when GLA had a once fortnightly BCal 1-11 for Horizon Holidays.