Stephen, just a word of caution. It's an extraordinarily bad idea to discuss this on social media before the trial. As anything you say here is a matter of public record you could very well be putting the noose around your own neck without even realizing it.
For your own good, I recommend you ask moderators to hide this thread from public view, although you may have already damaged your case more than you can imagine.
That said, I did hear about this accident when it happened. It would appear to me that the BSAC is covering it's legal patoosh here by keeping its head down and is going to watch this case carefully as are other agencies. What really appears to be under scrutiny here isn't so much the question of what when wrong during this particular dive but whether or not a buddy with an instructor qualification has a higher duty of care than a lower trained buddy, even if the dive is not a training dive.
Putting this in other terms if Stephen is found guilty it could mean to everyone out there that highest qualified diver in a group could be seen as criminally negligent if a rescue of their buddy is required and they fail to act before someone else does. All kinds of nasty complications could result from this.
R..