Paul I found that I was getting at least 3K from the medium compounds and spend plenty of time on track. Maybe time to you to get a cheap tyre temp guauge / sensor setup? Suspect they have got too hot - past their working temp and just killed them. I could get 5K on the road with a little track use. Also dont hang about on track
just in case you all think I drive like miss daisy lol
Not been on track in the car with you but you can keep the temps down in a car by adjusting your style of driving and smoother lines. The diff / setup of the car will let you get away with some agressive lines but at the expense of your tyres.
Be interesting to see how it does on slicks but again I feel you have to drive a bit different on slicks - just my experiances
Hope this helps in some way