That's cool which A-levels are you doing? Yeah a degree requires effort whether you do it through OU or a brick uni so might as well do what works best for you.
Those are interesting courses, Have a look at the moodules offered on each course and see what interests you the most. And if you still can't decide the OU offers Access courses, that explires different disciplines, although the psychology access course is seperate from the business & law access course.
I applied for BSc Computing and decided to study part-time to ease myself back into studying. It's only been a year but I need to refresh my study skills lol