Thats not the right grommet in your picture under the scuttle. There is another to the left between the black airvent and the ECU box, roughly inline with the battery. You have to get down low and look up into the space under the scuttle to see it. A round black thing the size of a 10p
I used some twin and earth electrical cable as a draw wire (ie stiff cable), pushed through the hole and it appeared in the passenger foot well without taking the glove box out.
BTW the two plastic things that hold the foam trim to the underside of the passenger dash unscrew (cos I snapped one off whoops!)