I'm actually still quite impressed with the HBA on my GTD, so much so that I made it permanent by coding it to Auto in VCDS, and lowered the speed at which it comes on to around 30mph (the slowest I think).
To turn it off, I just push forward on the high beam stalk, and again to turn it back on. Also, moving the light switch away from auto will reset the HBA to off and I then have to manually set it to on again, but it will remain set (even after stopping and removing the key and restarting the next morning), for so long as I don't over-ride the auto setting as mentioned above.