auto answer ios10 - Bluetooth Headset

So having seen quite a few "Solved" questions, saying yes.

I note that none of them say how...

So I have a tiny bluetooth headset that fits nicely in my ear and under my motorcycle helmet.

However there is no way of pushing the button to answer, so I want the call to route and answer.

I've tried the settings - general - Accessibility - Audio Call routing to Bluetooth headset, but that just routes it, in no way does it auto answer.

I know some bluetooth headsets have additional functionality to do this, but the one that fits most comfortably for me doesn't and besides, I want the phone to do it!