Echoing what DrDusk, Sine and Tau said above, it's definitely not a necessity to have a tutor for methods, or any other subject for that matter, to get above 45+; likewise having a tutor wouldn't mean you're bound to get a better score. However, I would say that in some ways, it will make it easier.
Talking from my own experience, I've never done maths tutoring in my life until halfway through year 12, when I started 1.5 hours of small group tutoring a week for methods. At the end of the year when I was starting exam revision, I found that I had a much more solid foundation in unit 4 than unit 3. My tutor also told me many tips and the things commonly used to separate top students which my teacher at school never told me, and I did find that they helped me on the exam - I got a 50 in methods, and while I don't think I would've scored significantly worse without tutoring, I don't think I could've gotten 50.
However, if you're prepared to go out of your way to prepare for the exam independently, then tutoring isn't needed. Another thing to beware of with tutoring which I saw in a lot of students at my school is: many students think that as they get tutored, they're "covered" in terms of content and don't pay much attention at school, which leads to having a much more relaxed and careless approach to study. In this case, I would say tutoring actually does more harm than good. For all the subjects I got 45+ in, methods was the only one I did tutoring for. So yeah, definitely not necessary, and depends on the person.