You should submit all relevant evidence that supports your complaint such as emails, details of witnesses and their statements (the Students’ Union can advise you on this). The Investigating Officer will rely on your evidence, so it is important that you include all relevant documentation at this stage of the complaint.
As well as any supporting evidence, you should also provide a copy of the Stage 1 outcome letter/email.
Please be aware that your complaint and supporting documentation will need to be read in detail by the members of staff involved so your complaint should be succinct (ideally no more than 3 A4 pages). Bullet points, rather than blocks of text, will help you to highlight the issues you wish to bring to the University’s attention. Normally, the number of pages of supporting evidence should not exceed 30.
Remember, the onus is on you to present sufficient evidence to support your complaint.