I actually did the A&F assessment centre a few months ago and start work there in naas in august. I found the assessment centre similar to the others i attended, apart from the fact it lasted two days and i had a night to prepare the presentation part for the next morning, other than that no prior research is really needed outside of knowing about the core strengths of the company.
The salary is also decent (dont really want to post it up, but if your really interested PM), and is what i would consider to be slightly more than allot of companies offer, there is also a very generous relocation bonus if you require it (i'm moving from england to ireland).