I cannot emphasise enough that pump failure is not in itself a scenario that will result in gearbox failure
I am sorry, but until this investigation is complete you have no way of knowing that. You are basing that statement on past history only.
I will say again, the prudent thing to do would be ground all S92's until there is a definitive cause. What would be the result of that? A few guys will have to ride to work in boats for a few weeks. The other scenario is just not justified in my opinion.