Toggle iOS on-screen keyboard with BLE HID Keyboard connnected - SOLVED!

I'm setting up a Puck to work with my iPhone as a BLE keyboard, all good so far but iOS has an annoying habit that it disables the on screen keyboard if there's a hardware one connected.
You can toggle the on-screen keyboard using the eject key on Apple Keyboards, which I belive is keycode 0x92.

I'd like to be able to send this from my puck so I don't have to keep disconnecting the keyboard in bluetooth each time.

Any ideas how to do this? I've tried

NRF.sendHIDReport([0,0,146,0,0,0,0,0]

and

NRF.sendHIDReport([0,0,0x92,0,0,0,0,0]

without any luck