No need to apologize, @FlagrumThorn- this is a very interesting topic! 
I can’t say I knew much about the 3 Knocks, so I did a quick search and read a few articles. For anyone else who also isn’t familiar with it:
The 3 Knocks are an old superstition. The belief is that anyone who hears 3 knocks in a row with seemingly no cause will soon be notified that someone they know has died.
This article on LiveAbout talks more about the history of the superstition and how it developed over time.
I personally have never heard the 3 Knocks (and knock on wood to that!). I think it is fascinating that you heard them over such a long period, @FlagrumThorn! May I ask if the superstition came true for you? If not, there’s also the possibility that you were being haunted by some kind of teasing spirit over the 8 months. And eventually they left to haunt someone else 
Has anyone else heard about or experienced the 3 Knocks before? I’m curious to hear everyone’s thoughts on it! 