[FatBoy]

I'm sorry, I don't know what "up in Cairns" means with regard to tyres, but you don't need to track your Cobra to get the benefit of the Avon tyres. They are outstanding and look almost as good as the Goodyears.
If "up in Cairns" means the temperatures are cooler, then that is even more cause to fit the Avons in my view. I'm in the UK, which isn't renowned for its high temperatures and the Avons work extremely well at cooler temperatures.

Paul