A customer suffered a cut eye, chipped tooth and bruising after he was attacked in the men’s loos in The Loft on April 5.
The victim, in his early 30s, was knocked to the ground, punched in the face and kicked just before midnight.
He was taken to the DGH where his eye was stitched.
Two men in the toilets went to his aid and police are keen to speak to them.
PC Nikki Desouza said, “The victim was out with friends when he was the victim of a nasty unprovoked assault. Any information from the public would be welcome.”
A 30-year-old man from Brighton, was arrested on suspicion of assault. He was questioned and bailed until Wednesday, May 6 while enquiries continue.
Anyone who saw what happened or who may have other information is asked to email email@example.com or phone 101, quoting serial 1491 of 5/4.
Alternatively they can call the independent charity Crimestoppers anonymously on 0800 555 111.