Agreed Elbert. But the principal operator here has certainly taken uncertified divers to and down the BH - I've been on the boat with one of them. Maybe not recently, but it has happened in the last few years.

As to the depth, I've always measured the maximum depth achieved by any divers in any groups I've been with, from six different operators. Frequently the 130ft "limit" has been exceeded, though I've never seen any recreational diver go below the shelf. On one such dive I stayed with the group throughout and we were at depth for 11 minutes before commencing our ascent, by which time my computer was a long way into deco. It still showed 20 minutes' deco when we returned to the safety tanks. Since I was the only person on the dive with a computer - the dive leader had a bottom timer and I didn't see any guests or other DMs with computers - only I knew what had really happened. The divers all thought they had been to 130ft whereas most had been to 150.

But as you say the dive is well marshalled. Every person on that dive made it back with no problems and I didn't hear of any delayed DCS in the group. So I'm not that worried, though it isn't good practice.