Surely if the principal mission is defence of the Clyde in support of the Nuclear Deterrant then a Scottish base makes sense? Re-investment in HMS Gannet perhaps (be quick though as it decommissions shortly with the removal of Gannet SAR Flight)?
Although a multi-misison aircraft like a P8 is an excellent ISTAR asset Waddington doesn't make a lot of sense IMHO. Airseeker is the replacement for Nimrod R1 isn't it?