A 27-year-old woman and 33-year-old man from Camberley were arrested on suspicion of making off without payment, and inflicting grievous bodily harm without intent.
They have both been released under investigation.
Surrey Police are appealing for help from anyone who may have witnessed the assault on the taxi driver in the early hours of Sunday, 19 August.
At 1.35am, the police were called by a taxi company who reported one of their drivers had been assaulted near Deanside. The victim, a man in his 50’s, received a severe cut to his scalp and had to receive stitches.
Detective Sergeant Mark Butterworth, who is investigating the incident said: “This was a violent assault on an innocent man who was just doing his job, taking people from A to B.
“We are keen to speak with anyone who may have seen three women and one man getting out of a taxi, or saw anything around the time the incident took place.
“The injuries the victim received are being treated as grievous bodily harm.”