Mysterious walls in the Canal Trench

It's in the last few days of the dig that the really promising structures have come to light in the canal trench, but there is little time left to investigate this collection of walls lying closely against each other horizontally and vertically. They are certainly mediaeval, and must be part of the original hospital. The last picture is of the gallant garden trench workers, who have had lots of mixed finds, but no structures for all their hard work.