Norman observed that his rear mats slid around between the rear
seat and the jump seat....

Here's my solution. When we bought our EV we stopped by the local
carpet store and bought a large piece of grey carpet for $5 or $10..
dont remember..we popped out the jump seats and the little trim
panel below the rear seat.

Then we laid out the carpet and cut it to fit a little bit under
the rear seat as well as to the front part of the rear cabin. We
cut little notches for where the jump seats clip into the floor.

Next we took the cut carpet to the carpet place and they put an
edge binder on it for $10. 

When we put the carpet back in the van, the jump seats then
hold the forward part of the carpet in place. We punched two
holes on the rear edge of the carpet and ran a couple of wire
ties thru the carpet and around the bottom frame of the rear
seat....

VOILA! No movement in the carpet...and all this for around $20!!!

Ric