This doesn't surprise me. I was at a lunch in London a couple of months ago where the speaker was the CEO of Norwegian and he was very clear about his philosophy which is, as far as possible, to link destinations both of which are attractive to tourists so that he gets demand in both directions on a route. As such, whether or not some of us might not like it, US tourists are more likely to be attracted to visit EDI than GLA/MAN/BHX etc so EDI was always likely to get the nod as the second UK departure point after London. At the same lunch he also said that if LGW gets a second runway he will build up to a fleet of 50 787s based there plus a multitude of 737s.