The attack happened outside the Grainger Street branch shortly after 2.30am on June 24, following a verbal altercation. The victim, a man in his 40s, was assaulted after the group was refused entry. Northumbria Police have released an image of a man they wish to trace as part of their investigation. He was believed to have been in the area at the time and may have information that could assist them. A police spokesperson said: "The man, or anyone who knows him, should send a direct message to Northumbria Police on social media, or use the live chat or report form functions on the Force’s website."