Raf aptitude testWatch
Seriously, go for middle ground. You want to be comfortable as you're going to be sitting down for a long time, so go smart casual but not jeans. Trousers and shirt, even a polo shirt, is fine. You aren't judged on dress at rhis stage, but you dont want to feel at a disadvanrage and be put off by other people arriving looking smart if you are realky dressed down.