I had mine almost a year ago and it was very informal and the girl was friendly and helpful. I got my date for interview after a few days, so the document check isn't really anything to do with the interview. Having said that, I had a feeling that the person conducting the check could add a note to my application. For example if I'd struck her as being stupid and dishonest, or conversely ultra keen and brimming confidence, she might have left a note 'this one no good', or 'we've got a good 'un here'.
So...nothing to worry about, but don't go in and put your feet on the table!