It’s going to happen at some point - whether the sensible P-8 order now or an open competition (which could end in disaster - a maritime Herc? Pull the other one).
Lossiemouth won’t take a big MPA - it doesn’t have the infrastructure (for example the taxiways are unsuitable for P-8 - visitors have to backtrack on the runway) and a consequence of SDSR 2010 was of course that the maritime community was sent south - how many are left and want to go back to Scotland is another matter. When I went through training most dreaded the possibility of being sent north at role disposal. From a retention point of view (particularly if the Armed Forces pay rumours in today’s papers are true - professional roles with external equivalents - eg pilot - will become very unattractive to high quality candidates) it could be a disastrous move.
More likely we’ll see a Southern MOB and deployed personnel oop north on rotation if it happens.
Regarding basing, everything I’ve seen and heard would point to any MPA/MMA going to Waddington with the rest of the ISTAR crew.
There have been mixed messages over a P-8 buy in the last week or so, but it still looks a safish bet…