MartG
I'd be wary of direct flame on the stone, very likely to crack it.They say (in my own words) heat the stone from a cold BBQ, resting on the pot stand, at maximum heat for 3 - 5 minutes with the lid on. Sprinkle flour on the stone, reduce heat to minimum and bake pizza for 8 - 10 minutes, also with the lid on. Leave the pizza stone to cool gradually. Never wash, scrape off any debris: they perform better once "seasoned".
Previously, I have always placed the stone on the griddle to distribute the heat.
I'd agree with Skewif earlier - the knack is to get an even heat below (stone) and above (to char the toppings), the stone would be too hot without a deflector - with the Safari Chef 2 I put the stone on the (cold) flat griddle pan, heat gently for 10 mins, put the pizza on and crank up the heat to max, with lid on, should be done within 10 mins...
Also use coarse semolina instead of flour to stop any sticking. Do what works for you & enjoy