Hmm... my real marks were pretty much the same as my mocks.
For English Lang I was predicted a B, and got an A*. I was soo thrilled (and the teacher as well, after telling me for about a month that it was extremely hard to get an A*... haha!)
For English Lit I was predicted A* and got... A*.
For Spanish I was predicted A and got A*.
For Math I was predicted B and got A.
For History I was predicted A* and got A. Oh well..!
For Biology I was predicted A or B and got an A*.
And for Art I dunno what I was predicted. Anyway, I didn't expect any higher than the B I got. I'm crap at drawing.
I think that, in general, your real marks are higher than your mocks. At least, in my school, teachers used to tell us that they were a bit harsher so that we would study more and get higher marks in the real exams!