It is both impossible and child's play. The both vans have a three position fixed bench in the rear and a two position bench in the middle. There are three mounts for each row. This doesn't vary based on van.
But the two place bench in the second row is different depending on ordered configuration. The third seat for the second row has a support built into the second row two place bench. The seven seater two place bench is lacking that support.
You can swap the entire middle row bench for the type that allows three seats- don't need to use the dealer for the refit. But if you order a Seven seater, the two place bench will not work with the eighth seat.
As for parts availability for the bench swap, no idea. Perhaps Rob can help.
But the two place bench in the second row is different depending on ordered configuration. The third seat for the second row has a support built into the second row two place bench. The seven seater two place bench is lacking that support.
You can swap the entire middle row bench for the type that allows three seats- don't need to use the dealer for the refit. But if you order a Seven seater, the two place bench will not work with the eighth seat.
As for parts availability for the bench swap, no idea. Perhaps Rob can help.