Sorry, I wasn't as clear as I wanted to be.
I have gone over the catapult and am in the bailey (or courtyard or whatever). I found the T'rang arm, and played with the hanging dummy and all the control panels in the glass room.
The doors I'm trying to get through are the next big set that leads further into the castle. I'm assuming this is the way I need to go to get the idol.
Is my progress at an end here until I go through the mines? Or have I just overlooked a way to open these doors.
Thanks
<=ST