There is an Academic Appeal Procedure but this does not allow challenges to academic judgement, i.e. a student disagreeing with the opinion of a marker. However, the procedure can be used if there is an aspect of the assessment process that has not been followed. The university expect any points you put forward to be factual rather than opinion.
An example of a ground for appeal is if your work was supposed to be moderated (i.e. the mark checked by another member of staff) but was not. Your feedback sheet should indicate if your work was selected for moderation. It is often best to raise any concerns informally with the marker and/or Module Leader first.
If you do decide to submit a formal Academic Appeal the form can be found in the attachments on this iCity page. You have 15 working days in which to submit a formal appeal from the date the results are published by the Exam Board.