Mine too Muffin ...
I would pull in a slight amount of collective and lower a crack of throttle, looking for a response, and if not getting any, return to departure point ASAP. (the arguement is that you are over, so a slight reduction if the indications are correct shall not harm you, but it leads me to -> )
At the same time, if it is a governor gauge malfunction, you might just be sitting where you should be and not seeing that indication.
So that begs my next question? Could one in that situation tell if the engine is truly "Revved" by ear? (Assuming you have some time in it, you should notice an "elevated" noise level (maybe?)
I suppose there could be numerous permutations of this, dependant on what one wants to try.
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Marc