Picked this boot liner up from a seller on Amazon last week. Flexible rubber and a perfect fit - £31 delivered.
It's just a boot mat, not necessarily for sand and garden waste.That's the type for shifting bags of sand in and garden waste. Possible ticks my anti slip box. Downside is that the tray on the right fowls up one of your storage places. Keep my windscreen cleaning bottles and water on the right, electric pump on the left.
I'd get one of those if I was doing another house clearance with trips to the dump and charity shops. Got horse manure in the lower area of my Altea boot... good for roses but not good in your boot . I'd stopped doing grubby stuff by the time I got the Ateca. I'd whip that in and out as required.
It's just a boot mat....The "liner" bit comes in that it's got the lip all the way round to stop stuff dropping down to the lower level, the grott that you may be shifting on the tip run or muddy boots etc in the back. A standard carpet mat like the anti slip one I've got from the Seat catalogue looks good, does the anti slip well, doesn't block off the storage areas but will allow grott to fall into the low level boot. That is how I see it. (including holes in my boots bag where I still get an issue... change the bag )
So the liner is more practical for dealing with dirt but effects the side storage if it extends into them. I'd get one of those if I started another house clearance and swap back after keeping it in the garage - lucky no more house clearances, tip runs, charity shop runs and moves in the near future. Expect the liner is good for dogs as well. Horses for courses.