Well done for spotting that missing path. I wandered round Sandwich for some time, taking notes and photos. One thing I didn't record - is there vehicle access under a building to the northwest of your path:
https://www.openstreetmap.org/?mlat=51.276159&mlon=1.340678#map=19/51.276158/1.340678 Sure there was, but I did not photo that... 
