Dragon Age Origins/Awakening background sound bug

I've looked all over and can't find any advice on this, so I hope someone can help!

The issue is that the background sound for the wrong scene/setting seems to be overlaid over other scenes and settings. Specifically: crashes and bangs and creepy background music. I think these are meant to be for the battle of Amaranthine in Awakening. I first encountered the bug late on while playing Awakening - I think before going into the battle itself, but I can't remember. It was annoying, but Awakening is so buggy anyway I decided to try and ignore it.

But now I'm playing Origins and I'm getting the same battle crashes and bangs for completely inappropriate scenes too! Having played Origins through several times before I got Awakening I know the sounds aren't meant to be there, and I got most of the way through my current play before they started. It's really annoying and completely breaks the atmosphere.

This time the sounds started appearing shortly after a message about installing Awakening starting popping up when I hit play on Origins. Awakening is already installed, so this also looks to be a bug - I assume they are connected?

I wonder if the download/install for Awakening is corrupt? But I can't see any way to uninstall the DLC, only 'repair' (which I have tried and it doesn't work).

Also, this is an entirely different computer to the one where I first had the issue.

Does anyone have a solution?

Or can you tell me how to uninstall Awakening (rather than just unchecking it from the DLC menu) so that at least when I'm playing Origins I don't get the sounds?