I'll try to find this documentary...it will be interesting to see!
We haven't yet had the time to go to Baia...maybe in the next week we'll go there (I can't wait!
Regarding the links that you posted, a little note: in 1925 the archaeologist Amedeo Maiuri found the Crypta Romana that goes into the hill of Cuma and he believed it was the Sybil's Grotto. But it wasn't so and he continued his research. In 1932 he discovered another gallery that has a trapezoidal section and he thought it was the famous oracle. In reality this gallery, datable from around the IV-V century b.C., had a military function. You can see it in the Temple's photos...it's a wonderful building! It has a particular fascination...
Instead these are our photos