Judging by the success (thus far) of the NAS LGW base, and the long-haul plans etc, I think they are there for the long term.
Which type is utilised at the base when/if NAS actually take delivery of the NEOS for the use of "Norwegian Air Shuttle" ( as opposed to some other yet to be created carrier, or indeed a new wholly owned leasing company ) shouldn't result in peeps being turfed out, as the new airframes will possibly come with the usual "freebie" type ratings routinely offered by manufacturers.
Of greater concern is exactly what the "permanent" contract will look like ( & with
whom, as rumours suggest the one to be offered in HEL will still be through an agency ) and how generous it will be in comparison to the current "contract" one.
Feeling amongst the troops is that HEL & LGW will be competitive, but Spanish based pilots should brace themselves for a Vuelingisation of T's& C's. With the planned expansion an attempt to offer conditions like that will be a little brave, but when you look at the woeful Long Haul contract, anything is possible both good & bad.
From March, we will have the 1st indication once we see the HEL offer. We are all watching with great interest.