Officers were called to Budgens on The Avenue following reports of an assault on Friday the 25th of July at 6:50 pm.
The victim was taken to hospital after the suspect allegedly smashed a bottle over their head during an attempted theft.
The suspect is described as white, with brown hair, about 5ft tall, wearing a denim jacket, black top, black shorts, and black shoes.
Anyone with information is urged to contact police on 101.
