Are the mocks, for example at FTE Jerez, harder than the actual EASAs? Been getting god results in them but want to be sure they are a good indicator.
As mentioned above, the mock exams are more difficult than the real exams, since the school wants to make sure that you are really ready before they sign you off for the real exams. I can confirm this since I'm currently in the final stages of preparation for the ATP exams.
Regarding the difficulty level of the exams, from an academic standpoint and as previously mentioned, it's not that difficult and one certainly don't need a degree to get your head around the stuff! What's rather more of a challenge is the sheer volume of all the subjects, it's overwhelming! My advise would be to get an overview and brake it into small pieces, work mainly with the Question Bank, make your notes accordingly (for later review -very important) and at the final stages focus on your weak areas/subject(s).
Another thing which I found quite helpful, the list which shows the distribution of questions per subject for the final exams, your flight school should be able to provide such a list.