Thanks for that, Kage. Strangely enough, I fixed it by other means.
I simply re-installed the driver and software. Now, I hadn't restarted at that time since I had also disabled the high definition audio bus, and so I don't know whether it was the disabling or the reinstall of drivers that fixed the found new hardware problem.
But, it fixed the changing mode problem. Well... I think so. I set the initial mode to entertainment mode, which is what I wanted. But now I'm too scared to change it again
But thanks for your help!