Hey, I reached the AC last year. I do not know if they have changed the format but last year it consisted of a written exercise, presentation and face to face interview:
1. Written exercise
Typical M&A case study, be concise, to the point and watch the time. I would also brush up on aspects of a successful/unsuccessful M&A - financial considerations (e.g. balance sheets, currency changes etc) or international elements of a merger for example the ability to diversify products in different markets. Always leave 5 mins to read through your work as attention to deal is highly valued, especially grammar and spelling. Practical point - bring a highlighter and sticky notes so once you have skimmed all the documents, you can easily find certain documents within the case study to back up/disprove your point.
2. Presentation
Last year, GR emailed us the presentation question in advance.. whatever the chosen question is this year.. I would research the topic properly inside and out and try and link every point to Lathams. Also prepare to be asked alot of questions from your application form whether that would be why you have chosen x subject for A-Levels.
3. Face to face
Typical questions such as why law, why lathams and how they differentiate themselves from their competitors. It is also a very personal interview in that the interviewers will ask you questions that stand out from your app such as your linguistic abilities or your extra curriculars. Also, do not be alarmed with random questions such as how many dentists are there in the UK? questions like this are really designed to test your ability to come to a logical conclusion (think of it like maths, you always show your working out before you conclude with your answer).
I hope the above helps, good luck with it all.