Cheers guys, I guess the Kenton device is our best option.
@SYNC, I can see the confusion now, piano = master controller, synth is what she’s trying to control over MIDI 
I agree I would’ve gone with a piano with native MIDI out, but the budget was quite tight and this Yamaha ticked all the other boxes. She was picky over the keybed and sounds so the options were very limited, and to be honest this is by no means a bad choice. She played it live today and she was clearly very happy with it 