A few of us are heading to the ring next month, this prompted me to look into insurance options. As far as I can tell, this is the situation:
Normal UK policies specifically exclude the 'ring. They are allowed to do this.
Track day insurance companies exclude 3rd party cover. They are allowed to do this.
So, no matter what cover you have, if you use the 'ring, leak some oil and cripple a few people by accident, you'll be paying for it for the rest of your life.
I think I'll just spectate!