When I first posted this I had no photographs of the Hovertel or later Pegwell Bay Hotel, nor of the beach showing caves. I now have those thanks to a person involved in Thanet (Kent) local history so they have been added!
Odd that you find mention of "something coming from the sea", etc. at coastal locations.
Back in the 1970s I was in Kent. Ramsgate's outskirts to be precise. Not far from the Hoverport (hovercraft) and Hoverport Hotel which was situated above the beach with , below it, caves I believe were once used by smugglers.
My father worked there a short time but I got to know the "Doorman" -six feet seven inches of bulky ex-para and a no nonsense man who had been in some very tight situations in the military.
One evening the owner said some barrels needed bringing up from the cellar which was within the caves. The ex-para went silent and the owner looked at him and told my father to go with "Dave". It was obvious something unnerved the ex-para and that itself needed explaining.
He later told me that he had gone down to the cellars himself one evening and was checking on barrels and suddenly became aware that the temperature was dropping fast. "I heard something like voices and saw...something" He would not say what he had seen but told me he had made it up stairs so fast he "was there before I even realised it!"
I believe the Hoverport is gone now but not sure about the old Hovertel.
I'd love to spend a few nights in those cellars because if there is something in those cellars that scares the crap out of a man that big -and he was also very intelligent- so much that he runs up a steep flight of steps and would never go down by himself after dark again...I want to see it!!