Tyre size

Moin, I would have a small problem with a vehicle registration in my vehicle license. I have extended my fleet with a New Beetle Revival. Now I have the problem that he has registered the tyre size 255/30 ZR 18 in the vehicle license for the rear. On the rims, however, currently 255/35 ZR 18 are mounted. Now, of course, I have problems with HU. Current status is an employee of the inspection center TÜV Nord gives me a winter employment and indeed all tire manufacturers abt Could be that this size was made and taken out of the program again, his words. Currently I have several named manufacturers off the phone, no possibility to get 255/30 with 18 inches. Does one of you have an idea whether there is this size on the German market at all (once) or a wrong entry in the vehicle letter/scheme. Thank you for your answers Jens