Someone on UK Cavers suggested I post on here since there might be someone who knows more about the strange goings on in my back yard!
When it's a quiet & still night and you sit out back above the house, you can quite distinctly hear the sound of dripping water, just as you would sat inside a large cave.
By the looks of things I'm sat between two known cave systems, however the dripping noises come from all around you ... it's quite something to hear - sounds like a huge space to my untrained ears!
https://44d18053-a-62cb3a1a-s-sites.googlegroups.com/site/cavesofnortheastwales/18-caves-p---s/OHA area DONE D (Custom).jpg
I found this image, and I live between the area marked for the poacher's cave & to the left of the words 'underground dome', but there doesnt seem to be anything marked and the dripping noises come from all around you ... it's quite creepy tbh!