After some internet research about exploding terracotta, I did some blue Peter style crafting.
Given the great price of the kamado, I didn't want to eclipse the price with expensive accessories.
After reading the post higher up about using sand. I had a dig around the house and found an appropriately sized cake tin.
I used some old skewers to bend hooks so the tin hangs into the firebox and leaves a nice gap for airflow.
I'll fill it with sand and probably wrap it in foil to keep it all together.
Will report back after my next low and slow.