In my personal statement should I talk about what I want to do after university?

If you have a clear idea of what you want to do in future then mentioning it will make you sound ambitious which is a great way to get the admissions team's attention. It will give the impression that you are certain you have chosen the right course. Their aim when they accept you will be to help you achieve your dream job.

If you don't know yet then don't mention it. It won't affect their decision. I didn't and things worked out well!