Gatiepie intersting question, i actualy asked Mr Da Silva @ Alpha today and he said as long as you keep it chilled it will be fine for another days fishing.
What i normally do is i pack a couple of ice bricks in my cooler box, place it on top of your Chokies and keep box closed when not in use, also i have been told that chokka will change colour once it goes Off, i think it's pink...