There is a process for appealing against academic decisions which is set out in the University Calendar, which can be found in the Library and on the web. In brief, a student would first discuss their problem informally with the tutor or lecturer who made the decision and try to get it resolved that way. If it was a tutor who made the decision, the student can also take their appeal informally to the lecturer, and if it was the lecturer then the student can appeal informally to the Deputy Director of Postgraduate Coursework.

Some examples of appeals that would not succeed: mere disagreement with the academic judgment of a lecturer, or with an advertised marking scheme; requests for additional points to get to a pass because you need it in order to progress or graduate. Some examples of appeals that will succeed, if the facts bear out the appeal: lost marks, advertised marking schemes not followed, changes made to assignment specifications within a few days of the deadline.

Students have 3 months to appeal once the problem has arisen. Appeals should be made sooner rather than later to avoid difficultes, for example appeals after semester ends about problems during semester can be impossible to fix because tutors are not required to remain on site after semester ends.
If the problem is with an exam then the right approach is to attend the school's examination review day where you can view your exam and decide whether you want to appeal against the marking. The dates of exam review days are advertised on the School's website.

If these informal approaches do not resolve the problem, you may decide to take the more formal approach of putting your appeal in writing and sending it to the Head of School, who is then obliged to acknowledge receipt of it within three working days, try to resolve it within ten working days, and then reply to you in writing giving the decision and reasons.

Appeals against the Head of School's decision to the Dean and ultimately to the University Senate are allowed for. See the University Calendar for details.