Hi Mike
It's very confusing, isn't it? Especially when an ordinary product can say it's gluten free but still have wheat in it. I'm pretty sure I've been glutened by glutafin's cake mix, which isn't wheat free. I tend to wonder, how many codex items would I have to eat before it becomes bad for me, and why should I try to find out? But, as Nikki says, it is a personal thing and we do learn by trial and error.
As for breakfast cereals, the supermarkets do stock several good ones in their free from sections. Alternatively, try eating aomething different for breakfast. Do you like pancakes? I get Schar flour mix C on prescription. That's totally wheat free and makes the best pancakes in the world
As for bread, I'm yet to find one I'm really happy with. I've chosen not to have Juvella because I'm trying to be dairy free as well as wheat free. Where do you live? If you've got Waitrose in you're area, Antoinette Saville does a bread there which is very good indeed.
Let us know if you need any more help on what to eat. Also, make sure you send off for loads of freebies to try everything before spending loads of money.
Susie