Cooking with a pizza stone As per a recent question of mine I intend to use the underside of an old granite chopping board as a makeshift pizza stone, once I've finishing testing that it won't break due to thermal shock..

Do I need to do/know anything in particular for this to be successful?
Does the stone need seasoning, and if so how would I go about doing so?

Also, if I'm having a lazy day, will a pizza stone work well with a shop-bought frozen/refrigerated pizza?
Or it is strictly for those that I have freshly made?
The stone requires no seasoning.

To prevent pizza from sticking to it you should dust it liberally with cornmeal before slapping a pizza on it. 

A pizza stone will not work well with a frozen pizza. The stone surface will simply be too blazing hot for it. You'll likely burn the bottom while still having a frozen top. There should be little issue with a refrigerated pizza, although I have not tried. However, you will want to be sure to let the pizza reach room temperature before cooking.

Update

Regarding cornmeal. I just realized that you're in the UK, and I'm not sure if you guys have a different term for it than the US. I'm referring to this cornmeal. You should also use the coarsest possible.