Two people have written to me to say they don't know what the red stump was that I photographed as a piece of neglected conservation. Perhaps this will put the stumps in context. It's the base of a column, one of those broken during the air raid that razed the cathedral, as seen here on the bottom right. There was a chip out of one and the loose stone is in danger of being lost.
Perhaps I shouldn't have assumed it was obvious.