[Johnno]

How should I be adapting my technique to avoid this result? And can these tyres be rescued? 

I used to use IsoPropyl Alcohol - IPA Isopropanol 100%, dab a lint free cloth in the IPA and run this on the tyre, as the IPA evaporates it cools the tyre down. I've since switched over to Shellite whihc does a similar thing but I also use the Shellite to clean the tyres during racing, works a treat. 

The Shellite will melt the rubber back to some sort of normal before truing, to some extent, get the car on the track and the tyres come up a treat.

Johnno