The mat/carpet in my car has been slipping round horribly. The holes in the carpet which the oversize screws go through have ovalised horribly.
TBH My old car did the same, but it was younger, so hadn't got to the point to annoy me enough to sort it.
Now I suppose I could have stuck the carpet down with some tape or whatever, but for cleaning it's easier to be able to take them out.
So here is my solution:
Some double sided tape and a piece of emery paper stuck under where your heels sit, carpet goes back on top, and voila no more sliding carpet, but still easily removable.