I picked this up on Amazon US as a Kindle book for a few bucks, well worth a read. First published in 1965, it plays as high camp horror with shocking events occurring during rain storms and the final scene on a beach. Hubbard plays it very straight though, with a few small clues that the grotesque elements are intentional manipulations and not just nicely done hack writing.

An upper-middle class Englishman inherits an old house from a bad old uncle. He and his wife drive from London to the coastal village to take a look. Terrible events ensue.

I'm glad I found the author; I'll read more of him.