Hi I think it was definitely the baby rice cos he is still eating pear and apple and his nappies are back to normal with no sore bum. I have looked at the ingredients and is just rice with thiamin added, not actually a rice cereal, which is why I asked if there was a difference. I thought baby rice was pure rice and rice cereal had more stuff in it, which it obviously does if it contains soy. Will try the rice when he is a bit older and just stick to fruit and veg for now.
Thanks for your help.