When I bought my car there were splits on the inside sidewall of both front tyres.
They were about 50% worn , I contacted the manufacturer and sent them a few photo's .
I was told to go to my local supplier and get new ones fitted which I had to pay for, they would send the tyres to the manufacturer with the correct paperwork.
After the manufacturer inspected the tyres they reinbursed the supplier 50% of the cost price which they eventually passed onto me.
They didn't even ask what width wheels I was using, stupid really as I later realised after measuring them that the tyres were too wide for the wheel and this had obviously caused the sidewals to split.