And is the ability to deliver that lift with multiple different types currently efficient, or sustainable
Not only is the current Chinook-Puma "multiple different types" mix efficient (Puma is a
significantly cheaper way to move smaller numbers of people around in) it is critical; there will always be places where you just can't or won't want to get a helicopter the size of a Chinook into, particularly in urban environments where, funnily enough, we are likely to be spending a lot of time in in the future if you believe
this.
On topic, it will be sad to see the demise of the Sentinel and its capability however, with SH (2 types), FJ (soon to be 2) and AT (2 eventually?) all rationalising platforms it must be difficult for the ISTAR world to win the argument that you need 5 (soon to be 6) different platforms to deliver the admittedly wide range of capabilities they offer...