For combined honours, you are given modules from one subject and modules from another. For example, if you studied history and politics, two of your modules will be from the politics course and the other two from history.
If you do a combined honours degree in history, such as medieval/modern/ancient,classical,medieval history then your degree modules will be more specialised to your subject area.
For presentations you might, it might change next year with the modules. I do full history and in my first year I have had to do two presentations, whereas a friend does combined honours and has only had to do one presentation for history this year due to not being on the same modules.
If you are worried about presentations it's nothing you should worry about. When I did my first one I was panicking, nervous, butterflies in my stomache before I was about to talk, thinking the worst would happen, but before I knew it it was over. I did my second presentation the other day and I felt a lot more confident for it, I was more confident in speaking and not as nervous as before.
The university help you settle into doing presentations by doing it in a large group in your first semester, smaller group in your second semester, both of which you will only speak for maybe 2 minutes. In your second year you will have to do a solo one, they are only about 8 minutes long. Everyone has to do it so you're not going to be worrying about it. There are workshops that help you on it also. Chances are, every other university will do presentations as part of their modules.
I hope that helped.