Hi James,
Thank you for your reply. Yet this has helped me to find my bug. You use Wire.onRequest() for registering the interrupt handler. That is correct. My issue is that I first want to send a command so that the correct float (I have several) is sent back. I am also using this command for controlling the satellite Arduino. You need Wire.onReceive() to do this.
I am still fighting to get these two handlers working together. But your example has helped my a lot.
Cheers,
Cronix