You can concertina fold a large wing in a narrow space. Paragliders have been doing it for decades. I tried it yesterday with my 12m kite and it worked very well.
I was surprised at how easy it was. I thought the leading edge would be too stiff and the air would get trapped in the folds. It's actually much easier than folding a paraglider, which I have done hundreds of times.
It's done so you can fold a big wing in a small space and not drag it across the ground. It's also meant to avoid damage to the leading edge battens on a paraglider, but that is not relevant to an LEI kite.
Basically you s-fold the leading edge to the middle leaving a gap of 2-3 panels. Repeat on the trailing edge, then roll over the s-folded panels to lock in the s-folds. Repeat on the other side. Fold the package as normal to put in the bag.