Most wear suits so if you don't want to stand out that's what you should wear. On the other hand your attire is not assessed in any way at the aptitudes as far as I know so it should not matter.....I would not go as far as the Jeans and T-Shirt example above but the fat that Woody got through would suggest it does not matter what you wear. Smart casual is OK and it might make your performance better if you are not wearing a tight collar and tie.
It is vital to look smart for Final Board if you get that far. Good luck.
Girt_Bar I don't think it's worth renting a suit, if you are travelling you might want to invest in a decent suit carrier. You can get these at most decent high street suit carrier shops
