CM,
You have a good grasp of the requirements - perhaps a little better than the present incumbent of 10 Downing St and those that would advise him.
My knowledge of MPA is limited to 27 years operational service, 6 frontline sqn tours, 5000 flying hours and an annual assessment in my log books (two) that reads "above the average" more times than not.
What is not being appreciated in these endless MPA threads, is that the vehicle is the smaller part of the picture.
You are totally correct in both your statements, that the RN is a more logical keeper of the capability, but it does not really matter if the RAF has it, and that no civilian organistion could mount this overall task. However, not only are the aircraft being dismantled and scrapped, much, much more importantly, so are the people who currently hold the chalice bearing 70 plus years of history, experience and training.
Because of that, the UK fixed wing long range maritime patrol capability is finished, kaput, extinct, gone to meet its maker and shuffled off its mortal coil.
And it ain't never coming back.
And if you wish to know why those that served before the "Galley Master" get so bent out of shape by some of the stuff on Pprune which appears on all these MPA/Nimrod threads, it is because not all the non-maritime posters have your educated view and they have no compulsion in posting the most utter geeky rubbish about the aircraft and service many of us proudly were part of for much of our lives.