Boot side on the right
 

The right hand access panel in the boot has that recess.

The one on the left has some netting over it, so its useful but the one on the right has nothing so not very useful.

Does anyone know why its there?

There are flat ones available. . I guess it may be to cause an illusion to make the boot seem bigger haha ..

I bought a spare and transferred the net from the left pannel to the right .. now have two netted ones +++ ahh the joys that a simple modification can bring aye

That sounds like a nice little mod.

Any pics?