Everyone's saying the same things. I think if you look at previous specimen papers, you'll find that they're often a lot harder than the actual exam paper, so you should have nothing to worry about.
But as for the style of questions/type of content, I'm not so sure myself as to whether it's going to change (pretty drastically) to be more like on the specimen papers. Unfortunately we'll have to wait and see.
I think I remember reading on one of the OCR or AQA science webpages that they would be releasing more material nearer to the exams? Does anyone else recall reading this?...