once again I have to concur with paperclip.
I did my S3 in February, and even before I did it back then, there were people posting on here saying their S3 had all been HR. IMO, the reason mine was more technical was because I already work in an occasionally demanding environment, but also i had read from a lot of sources prior to the interview, and so they wanted to make sure i had actually done my stuff, rather that just saying i had.
it would have been different if for example i had come straight from school, and had no uni or real work experience, then they may have been more concerned that i was not prepared mentally.
in short, revise both bits, you will hate yourself for failing if its because you tried to second guess what will be asked.
shugs