A young man and woman went into Pizza Plus on Church Street and asked staff if they could sit down. Shortly afterwards, three men and a woman wearing a red top and blue jeans came in and asked to speak to the pair.
The woman in the group is then understood to have asked the other woman to return a quantity of cash.
She has refused and a fight then broke out between the whole group.
All of the individuals are believed to have then left the area.
Enquiries are currently ongoing but officers would like to speak to anyone who was in the restaurant between 7.45pm and 8pm on August 25, who witnessed the incident or can help with the investigation.
Anyone with information is asked to call West Mercia Police on 101 or Crimestoppers anonymously on 0800 555 111 quoting incident number 818S of August 25.