As others said, mocks are not official so "cheating" doesn't have an effect on anything and doesn't matter since the results are forgotten as soon as you do the real exams - mocks are just practice.
But, I wouldn't recommend looking at the past paper mark scheme for other mocks, as the only reason you do mocks is to get you used to sitting the test and the exam environment, so if you have already seen the paper it will make you a little less prepared for the actual test. It doesn't matter a lot, you can always sit a "mock" at home, just print off a past paper that you haven't done before and set a timer and then do it in the time as if you were in an exam. This is generally good to do, gets you used to what sort of thing they look for in answers (you should mark your paper afterwards and see what you did badly in, then work more on that).