Really good question
So if CHF is the supposed maritime and amphibious experts, why is it in the JHC in the first place? If they love the sea and bobbing around so much, why aren't they under a maritime HQ?
And Unchecked, as to the cost for 'markfourinisation' of the Merlin, I would tread carefully there as we all know it is not purely the marinisation of the airframe that will cost the money, but the essential LEP to remove obselence (maybe even improve the cheese gearbox that everyone talks about?). Therefore even if we end up with the Merlins we too will also need to spend money.
If we were really being honest with ourselves I personally do not think that despite the forward leaning pretense by senior officers that any of us in the wokka or freak fleets genuinely have the appetite for many months at sea (and it looks as though the Libya Op is providing a non-intervention power projection template that the current genre of politicians like). Especially if all Merlin are going to be based in the depths of Cornwall - I can see wives and girlfriends just loving that as we all depart for 6 months at a time!
If the Fisheads really want to take Merlin to sea then good luck to them.