Here's another choice - trident itself, nil hours units. proven to work (without the sunshine package)
build a slightly bigger astute boat class with a bit bigger fin - (you see where I am going)
Insert 1 or 2 x Trident with BIG or Little payload choices
Add a team of about 6 steely eyed missile men to each boat and increase pies complement to match.
order 10 boats?? 20?? we than have a FLEET of kickass and take names subs with the deterrant dispersed aboard
Big consultancy fee please. Oh and to the nay sayers I seem to recall seeing a ducmentary about the astute being a modular build.
Q.E.D.