NCL-EXT has been once daily for sometime now (winter anyway) and some days not operating at all. Returns to twice daily (for 2 days of the week) in the summer rest is only once daily.......not enough people or just poor timings for business passengers? My theory - the latter.
NCL-LGW is 4 times a daily but only 3 days a week. The rest is a combination of 2 or 3 daily. (summer)
NCL-BHD twice daily (2 days a week) the rest only once daily (summer)
I assume a lot of these changes are a combination of low pax demand and to allow for additional services to summer routes JER and the weekly LIG