Many thanks MartinR.
It was one of the areas I had to clean of leaves, rubbish and other detritus many years ago before drawing the stonework in detail so I remember it well. (I was a much smaller person then).
The survival of the Roman wall was largely down to the early creation of Rochester Diocesan with the building of the early Anglo-Saxon church, which is beneath the west front of the present cathedral and its precincts. Forming a defendable enclave within the circuit of the Roman walled city of Rochester, it was subsequently reused as the precinct wall for the early Norman cathedral until they needed more space and pushed the boundary further out with its own secondary defendable wall. This internalised a section of the former Roman city wall as it extended through the priory buildings.
Here is my next, which is an addition to a fairly rural location, so doesn't appear on GoogleEarth, or StreetView