The women was attacked on October 25 between 2.45pm and 3pm outside Apple Green Petrol Station, on Bargates.
A West Mercia police spokesperson said a woman in a black Mercedes Coupe was seen filming the incident.
"We would like to identify her or for her to come forward," the spokesperson said.
"We understand there were three men standing nearby who may have witnessed the incident and we would like to hear from them too as they may be able to help with our enquiries."
Anyone that may be able to help should email Constable Laura Hazelwood at email@example.com or call 01432 347217 quoting reference number 247i of 25 October.