Ian,
Mate you are on your own. As soon as you sign anything to do with a motorsport governing body, no insurance. And that is 99.9% of insurers.
But dont let that scare you Ian, We put up cones to keep the speed down, and just drive to your limits on the backtrack!
Dont push them, while it is a fun competition - remember FUN comes first - its not a proper race to get the fastest time, its just driving quicker legally!!
Skid pan - again, go to your limits but not much to hit there