As long as you don’t roll up in trackies and high tops with a string vest; there’s no real right or wrong with what to wear. Something smart but comfortable is ideal; I opted for black trousers and a shirt and carried a blazer round with me (but didn’t put it on because it was massive and made me look like a kid in a school play dressing up as a businessman). I tied my hair back and steered clear of heels in an attempt to come across as low maintenance and didn’t go to town on the make up (not really an issue for most lads). Black, smart shoes are a safe bet and please don't forget to polish them - there's nothing worse than scuffed school shoes! Don’t spend your time trying to develop a “vetty” look; just make sure you feel comfy (so you aren’t focused on the blisters from your posh shoes or potential VPL in your super tight trousers) and look presentable; let them see you’ve made an effort to smarten up because it shows you care!
They will be assessing you for who who are and not what you're wearing, however don't forget this is hopefully the gateway to the start of your veterinary profession so you will want to look smart as well as make a good impression.