GNSS Power Modes not Working

I am trying to switch the GNSS module on and off using the methods enablePower and disablePower.

My issue is, when I call the disablePower mode this turns off the GNSS module correctly, but when I then call the enablePower method the unit remains off until I cycle the power/reset button !

Do you have an example of turning the module on and off or at least putting it into sleep mode until I need it ?

thanks