Geoffersincornwall, I understand your dilemma. But I'll take going against the checklist over a good chance of flying into a mountain any day. Alarm bells ring for me if a pilot is letting the legal implications of non compliance with a CHECKLIST prevent them from acting on a fire warning IMC over mountains.
In your specific example, I think there is a good case to amend the checklist detailing a course of action should the fire not be confirmed.
However the checklist also says a 1 or 2 minute cool down run prior to shutdown. If you landed a helicopter immediately say, due to an fire in the cabin (I haven't seen a checklist for that), would you sit there complying with the cool down run?
Blind compliance is not the answer for all possible scenarios, and there will never be a checklist for every scenario possible. We are there for a reason, and one being perhaps the ability to reason and sometimes make choices in the best interests of safety when either there is no checklist or the checklist just isn't adequate or appropriate for the given situation.
In my view we should continue to view the checklist as an aide memoir, and not a legal contract. The regulator and operator can mandate the level of compliance with it, and the exemptions justified in the best interests of safety.
Otherwise are we not only designing the pilot out of the cockpit, but also legislating them out of it?