Having qualified as an ACA (big four trained), I just wondered at what level I should look to be applying at a strategy consultancy firm? Would I essentially be applying for the same job as a graduate or could I enter further up the ladder?Furthermore, what are the hours and culture like at a top consultancy firm and what is the view on work-life balance?

It's unlikely you'd start at graduate level, although firms differ between how much responsibility they will start you with, and how much they will expect you to pick up through accelerated promotions, but either way your ACA will count for a lot. Unless you have 3+ years post-ACA experience, or very relevant industry experience for a practice area, you should look to be within sight of the MBA hiring level within about 12 months, depending a bit on which firms you are looking at.Hours and travel vary a lot, and not always predictably, which is one of the main impacts on work-life balance, but will be more than is normal for a typical big-four practice. In general it's bearable if you are genuinely interested in the work (DON'T do it if you're not, it's just not worth it) and ambitious for further career development - ultimately, I think it's a trade-off to go into with your eyes open. Assume no more than 60 hours a week on average, but with a wide variance from week to week.