The assault took place at around 9.45am on Tuesday 14 August after an altercation broke out inside the Mobile Care phone repair shop on Northgate Street.
It’s believed that the man pictured went behind the counter and tried to assault the shop owner.
Another member of staff tried to calm the offender down but he then then went on to assault the employee causing an injury to his hand.
The offender left the store on his red mountain bike and rode towards Eastgate Street.
If you recognise the man pictured please call 101 with incident 108 of 14 August.