Students cannot appeal against the academic judgement of the examiners. If you have concerns about the mark/feedback you have received for a piece of work, you should discuss this with the Module Tutor or Programme Lead.
All work goes through the University-s marking and moderation procedures. External examiners are also involved. More details on the marking and moderation procedures, and the external examiner process, can be found in sections 30 and 42 in the Code of Practice. Your Module Tutor/Programme Lead will be able to talk through the feedback you have received.