Wizz Car Hire

Look here:

To view the CROSS BORDER or FERRY terms and conditions. At STEP2 of our 3 step online booking process, alongside the car photo of your choice, there is a link entitled “IMPORTANT INFORMATION”. Clicking on this link will open an additional smaller window, with the terms and conditions appertaining to that particular car/supplier. Choose then the CAR tab and look under TRAVEL RESTRICTIONS Try a few different suppliers as each supplier/vehicle type may have a different cross border rule.

The website will show you cars if it is possible and show you the suppliers who have vehciles available. I can see AutoUnion is not in the list with suppliers that have cars available. You can select a certain supplier if you only want to see cars from a certain supplier with the " supplier filter " at the left hand side of the results page.