Hi Rowan
Thanks for you kind words. I had to use a walkthrough to get through the quest with the exploding room. I suppose this is what you mean? or? I must admit I never had any problems with this, especially after reading that you just use use the Rift travel system to transport your party to the beginning of the cave.
As said, I find the journal or log very badly organised. There needs to be a journal for the main quests and a journal for the sidequest. And preferably for each major area, I find. I also find that there really need to be a marker or something else which shows you where you have have found the 12-14 stones, you'll need.
As for your problem, Rowan, I'm aware of it. On the Larian forums, a guy? did experience the same as you have done. And the answer was that the switch probably was damaged in the explosion.