Focus + OIHID

[Ranma]

One of the players in my game wants to play a character that has a suit of power armor. This is taken as a focus, but because the suit could not be used unless worn , he wants to also add Only in Heroic ID. As opposed to say a ring which is a magic focus that must be worn but doesnt constitute a different identity. Since I am the GM i can make any ruling , but i want to use the Standards, would YOU say this is a reasonable combination?

[Steve Long]

I'd say, as per the rules on 5E 197, that you should not allow him to take both. He should take one or the other to represent the special effect he has in mind.