It is your choice whether to report to the police. If you are in immediate danger or seriously injured call 999.  If you feel unable to speak, the silent solution guide  means that the call handler will be establish whether you are in need of assistance.  If you are on a mobile you will be prompted to enter 55 on the keypad which will put you through to your local police service.
You can also  report a crime using the non-emergency number, 101 or online.
You can report domestic abuse anonymously by calling crime stoppers at any point on 0800 555 111 or use their online form
Students and staff can report domestic abuse using the AUB’s Report and Support system. You can choose to do this anonymously or you can request support from a Wellbeing practitioner (for students) or an HR Business Partner (for staff).  If you choose to talk to a Wellbeing practitioner or HR Business Partner they will be able to talk through the options and support available to you, in confidence, or refer you to other sources of support. 
University Policies
If you choose to make a formal complaint to the University about a student or member of staff there are procedures which set out the steps you'll need to follow. 
If you’re a student:
You can report another student under the Student Disciplinary Policy.
If you wish to report a member of staff, you can make a formal complaint to the University under the Student Complaints Procedure.
You can also have an informal conversation with the Senior Investigating Officer so that you can make an informed decision about what action you may wish to take- contact 

If you are a member of staff:
You can report another member of staff under the Dignity at Work policy. Your HR Business Partner or Union rep can advise you on this. 

There are two ways you can tell us what happened