A man needed overnight hospital treatment after he was assaulted outside the hospital in the early hours of Sunday 8 August.
Police say the victim - who was in his mid-twenties - suffered facial injuries after being pushed down and kicked.
He was wearing a navy coat and jeans and was carrying an orange sports carrier bag.
The suspect is described as a white man between 25 to 30 years old, around 6ft tall, with receding short dark hair.
He was wearing a dark green top and similiar coloured shorts, and dark shoes with no socks.
Anyone who saw what happened or has relevant dashcam footage is asked to call police on 612612 or Crimestoppers anonymously on 0800 555 111.
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