I am guessing that the US distributor is SUV Cargo Liner | Car Roof Top Carrier | Pet Barrier | Hatchbag Inc. who I e-mailed regarding the liner. They replied that they did not have the product and were not aware of when they might get it. I'll try again in a few months, but I encourage you to ask and if enough of us do, then they may stock it on this side of the Atlantic.
I just ordered it from the UK. Shipping is pricy (50 British pounds) but they refund 20 pounds and it has a rear seat flap, a bumper flap, and only cost me about $240 with shipping total. Will post updates when it arrives.