So if it is not a broken dampproof course causing the dampness to rise, then what else could it be?
High abutting external ground levels This is where there is damp either at or above the line of the original dampproof course or at or above the level of the internal floor.
The construction of these in pre-Edwardian buildings are unlikely to have a physical horizontal dampproof course in the support walls below floor level, called the fender walls, these can "wick up", or draw up dampness from the ground below floors and introduce dampness on the walls of the chimney breast and reveal walls.
It may be surprising that all of the above are exclusions under a long-term dampness guarantee for rising damp and yet they are the most commonly-found causes, none of which require a retro-fit chemical dampproof course injection to solve them.
The only thing they may offer is a retro-fit chemical dampproof course injection and, of course, that peace-of-mind guarantee.