And resolved. Cage nuts fitted and thumbscrews fitted holding the carpet in place.
How? Pushed a cable tie through the cage nut, the head being bigger than the threaded hole so it can't fall off. Pushed the end of the cable tie through a larger circular hole and out the rectangular hole next to it then pull the cable and cage nut to the back of the hole, lifted the cable tie so that the lower groove pops out of the hole, pulled it a little tighter end and used a thin electrical screwdriver to depress the upper groove enough to pop through the panel and job's done.
Insurmountable problem sorted with 5 minutes thinking over a cuppa! Now to finish the tea. And move on to the next job.
Guy