A 29-year-old woman suffered 'significant head injuries' after a man attacked her in Kingswood.
Detectives have now released grainy CCTV footage of a man they would like to speak to in connection to the GBH.
A spokesperson for Avon and Somerset Police said: "The incident was part of a large fight on Sunday 16 December 2018 at 4.38am on Kingswood High Street.
"The man in the video is described as white, short dark hair, wearing a dark Xmas jumper, black trousers and dark shoes.
"If you can help with the CCTV or you were in the area at the time and saw anything which can help with our investigation, please call 101 and quote reference number 5218277356."
You can contact the independent charity Crimestoppers 100 per cent anonymously on 0800 555 111 or via their Anonymous Online Form .
No personal details are taken, information cannot be traced or recorded and you will not go to court or have to speak to police when contacting Crimestoppers.
