Wall of walled garden to S. of Cloister Hall

Rubble stone garden wall, partly incorporating on N side basement wall of Cloister Hall and, to left, end wall of C14 undercroft behind Cloister Hall. E side, to footpath, has door at right end. S side is embanked against outer side, facing cathedral. Square headed blocked opening at W end. W wall has low 6m length to SW corner then high 4m length, the front wall of a square tower presumably built over undercroft with access from raised garden of Cloister Hall, then lower 2+m section to NW angle. On N side, left end has low segmental arch into undercroft and then continues to basement of Cloister Hall with door into parallel undercroft.