This response is being typed in Edinburgh by someone who has lived in Edinburgh all his life, though events have caused me to visit Biddenden a few times for investigative reasons and am looking at these posts for the same reason.....it wouldn't be that one of your questions can be answered because of this
The suffix 'den' came across to me as relating to the archaeological discovery of tombs with mummies, enbalmed & wrapped etcetera, cultural difference being that the tombs separated male & female, one side for males on bunk-like structures, the other side for females in exactly the same structure
cannot recall right now how many thousands of years old they were,
wasn't it thought strange that something similar to the Egyptian phenomenon had been practiced? Am struggling to recall whether they were just one thousand years old, though.....these may have been called 'dens', thus the den suffix arises from the peculiar nature of the burial practice.
All the best from