Hi,
I did the A&O AC last year but completely bombed it rip. Make sure you practise doing a few case study interviews (I think TCLA has a few?). I would definitely say to brush up on commercial awareness - you'll want to bring in relevant stories when talking about the case study. The assignment is likely to be something related to M&A, so take a look at common contractual features like warranties, indemnities, etc. I also familiarised myself with finance-y type stuff like EBIDTA because you're likely going to have to do some maths. You're probs not going to be able to cover everything in the info pack in detail during the time given to you, so make sure to prioritise. Structure your talk clearly, keep your cool, and give yourself time to think before you answer any questions. Also, don't forget at the end of your presentation to actually give a recommendation to the (fictional) client, and be prepared to back it up!
I also had an interview with grad rec which was basically a verbal kind of situational judgement test, which is a lot harder to prepare for. I think I was also asked the classic motivational kinda questions.