Paul__B:
Ah, but it is not the state of the "two-way" relay that he wants to know, but whether the appliance is in fact on or off.Thus my point - the controller and relay exclusively controls the appliance, then there is no doubt as to its state, and you direct all forms of switching through that controller.
If you are going to use a controller - as for my house lighting - best do the job properly, "from the ground up". I challenged the concept that you would need some sort of "alternative" control to the controller itself.
I agree that that is what he probably should be doing, but we have no indication of why he needs/wants a two way switch.