I heard recently that non bio is a UK marketing ploy, and it's better (as in, cleans better and better for the washing machine) to use bio and rinse it out properly. Apparently modern machines use less water to be more environmentally friendly but that means that washing powder doesn't get washed out properly so you have left over bio detergent irritating sensitive skin.... none of us have sensitive skin so I just use bio and no extra rinse on clothes.
I don't know if other countries have bio and non bio?