Just my opinion of course (although one that many of my colleagues share) but the feeling is if/when the Bus arrives , it will neither be in NAS colours, nor based in Europe. The other theory is that the order was either placed to get the best deal from both Boeing/Airbus &/or to sell the delivery slots, &/or to block competitors ability to get a hold of new aircraft &/or to set up a leasing company & make some bucks that way.
There was a rumour doing the rounds at one point that NAS management had been seen visiting Vueling. . . . . .