Do we have a source for calling this "the secret waterfall"?

Doing an internet search for "The Secret Waterfall, Wales" give a different location https://explorestronger.co.uk/secret-waterfall-hike-in-snowdonia-wales/
Other one is in the Brecon Beacons.

One site does refer to 
"Blaenau Ffestiniog's hidden waterfall walk"
But that is to the east of Festiniog. 
https://www.loveouradventures.com/post/rhaeadr-cymerau-coed-cymerau-isaf-blaenau-ffestiniog
