My take is that in terms of based units then it's a bit of a numbers game & NCL is on the way down. The op's where BRS based frames commenced operating through NCL on the STN was in my view a nail in the coffin & there is definitely a resignation amongst based crew that the NCL base is contracting and that it could close at some time soon
On a more positive note I do recall that the NCL offering does tend to be placed on the website later than others and I can only summise that this in itself is simply a case seeing what remains after their committed bases have all been sorted. The general trend in any event is further migration and development of their European bases with the ensuing pressure on NCL crews amongst others to operate such routes.