I've got four car mats available. I think they were originally from a Seat Ibiza, but they might have been from a Puegeot 308. Certainly they have been in several cars.
One of the rear ones was chewed by a naughty dog (not ours!).
The driver one has worn through which is why we got appropriate ones for our current car.
Anyway, I wonder if placing one of the rear ones under the driver would provide reliable coverage (you'd have to check it was safe to do so in terms of slipping etc).
But whatever you want to do with them, they aren't any use to us anymore, so they are available to a good home/car.