Have you had a look at some specs/course content for those A-Levels? That may help you with your decision. Another thing to consider is, if you are thinking about uni, what course you may want to pursue, as many have specific required subjects/subject combos, though for humanities it's generally not so rigid.
Psychology, in my opinion, is nothing like what you think it would be like. Extremely interesting in practice, extremely boring in theory and study. My vote would then go for politics, but I love political theory. Again, choose based on what you prefer. Look at course specifications for the exam boards your college(s) use. Think about uni course (if applicable). Don't choose based off of the opinion of others, especially me, as I would go for eng lit, history and politics based off of those options. You have to study it for two years, after all.