"... jurisdiction to give an applicant or appellant leave to withdraw notice of abandonment of appeal or application for leave to appeal where the notice of abandonment could be treated as a nullity, i.e. where the abandonment was not the result of a deliberate and informed decision - in other words, where the mind of the applicant or appellant did not go with his act of abandonment. Headings such as mistake, fraud, wrong advice, misapprehension etc should be regarded only as guidelines, the presence of which may justify the exercise of such jurisdiction of the Court and are not exhaustive of the types of case where this jurisdiction can be exercised."