I visited here last month with my mother being quite an 'underground experience' fan, and I have to say I was very disappointed.
The leaflet made this attraction sound like it was going to be great for cave fans, and in fact rather terrifying, so at the reception I made a point to question the intensity of the Black Chasm. They said it was fine and put us down for the 12 version (The oldest). Now having experienced this tour I now feel stupid for asking!
Waiting for the Black Chasm tour to start, I overheard a few people say that their partners were not taking park because they were too frightened... they shouldn't have been! The group we went in with consisted of children clearly under 12.
We were then greeted by a male dressed up in a ripped costume with blood on his face with a very strong SCOTTISH accent. To cut a long story short, he lead us up to the cave stopping us every 2 minutes to make comments about either Justin Beiber or 'the cave gremlins having poos everywhere'... the children seemed to enjoy it but not what we went for!
The cave it self was the least referred to within the tour, if anything we rushed through it so quickly it was like it wasn't even supposed to be a cave tour! The only part I enjoyed about the tour was walking through the pitch black maze at the end, but even still, this wasn't made scary by the queue of people infront clearly identifying the way.
If you have children who like fantasy stories crossed with a little bit of immatureness they will love this, otherwise STAY AWAY and visit some where else. I went to King Arthur's Labrinth last year which was easily 10 times better!
This review is the subjective opinion of a TripAdvisor member and not of TripAdvisor LLC.