Yep, I’ve done it many years ago. We hired from a local company and made sure they were ok with taking it abroad and that it was in the T’s+C’s. Cant remember how we got around the booking with no reg plate though……
It was back in our younger more stupid days, trying to do it on a shoestring, there were, ahem, more of us in the van than there were seated belts put it that way (yes, stupid I know)….. we had it all planned to a tee, booked 2 guys onto the ferry as passengers in the van, the rest of us dived out of the side door in Dover on the road to the ferry and walked on as foot passengers, just in case we got pulled over going through. Reversed it at Calais and hightailed it to the alps.
All seemed to be going so well till we got pulled over, by an armed and uniformed officer as we were going through a toll road booth / gate thing soon after leaving the alps on the return journey. I was driving, I sh@t a brick I tell you. He asked to look in the back of the van. We opened to door and he eyed up our suspiciously ‘stereotypical illegal immigrant’ look a like friends in the back of the van sat on a mattress behind all our bags and bikes. After checking all our passports, he turned to me and said “it is lucky we are not the police”, before waving us away…… relieved is not the word. Made it home without issues, including going through the jumping out, foot passengering it, jumping back in rigmarole on the way back. Nowadays, I’d fly……