we arrive on the 30th June. Is there any clarity on how they will charge hire cars

Hi Scotbelle and welcome to the forum.

The subject of Tolls has created a huge amount if discussion, and you can read some of it here:

viewtopic.php?f=2&t=22790
viewtopic.php?f=2&t=22888
viewtopic.php?f=20&t=22121

There's even more if you search.
I don't wish to sound rude, but we don't need yet another topic, so I've just closed this one and hopefully you'll find the answer above.

... actually the answer to your specific question is "no further clarity", but watch this space !