Pirelli P Zero 245/35/20 tyre run flat

Used tyre with 6.5mm tread left. I believe new there is about 8mm on them. Been on car for about 5 months. Only have it as I got a puncture on one but had to change both tyres as was changing out to normal air tyres so kept this as it was more or less still new. One little knick from a stone but only skin deep as shown in picture. These were €285 new each so selling this for €150.