A man was punched to the ground before being stamped on the head by a gang of three who then fled. Witnesses are being sought – including a good Samaritan who stopped the attack – after what has been described as a violent and unprovoked assault in a town centre. The victim was jumped on at around 6pm on August 23 in Windmill Street, Gravesend. It is alleged a woman and two men approached him before punching him several times. After being knocked to the ground, they then stamped on his head. The trio, all believed to be white, then ran away. The woman had blonde hair and was wearing a blue tur…