NBLUCK LK250 Buggy Tyre specification help needed

Dear Sir or Madam,

I own a NBLUCK LK250 Buggy that is manufactured by your company (YONKANG MIRO VEHICLES CO., LTD.).
The vehicle identification number is L6RKFNZA10M000136. According to the EC certificate of conformity, the vehicle is homologated with front tyre size 21x8-10 and at rear tyre size 22x10-10.
My problem is now, that in my country the front tyre size 21x8-10 is not available at all. I currently run the vehicle with 21x7-10 tyres at the front but with this size I don´t get an approval by the local authorities. Therefore I ask you if you can send me a certificate, that the use of tyres in size 21x7-10 on this vehicle is allowed, too. Alternatively 22x7-10 would be also a possibility, but not my favorite.
Thanks a lot in advance and best regards,

Nils Muller