The incident happened in Penny Lane just after 6:30pm on the 2nd of August.
The victim fell into the river as a result of being assaulted and sustained fractured ribs as a result.
The suspect is described as a bald, white man with blue or grey eyes, around 6 feet tall with a very muscular build.
He was wearing shorts and driving a white car and spoke with a low to medium pitched southern English accent.
Any witnesses or anyone with CCTV of dashcam footage is urged to contact police on 101.
