I had the folks here last night to see the AB's claim the cup (phew!) and this morning the old man made me up a mount for the GoPro. It's a sturdy bit of ally bolted to the bike via the muffler hanger and has an old ball mount on the end allowing me to mount the camera facing either forwards or backwards. It has to stick out a fair way to see around the bike but looks ok when the pannier is on.
Seems to work fine and is a lot more sturdy than the suction mount. I also tried a different back on the camera housing - this one is not waterproof as it has ports cut into it to allow for better audio capture.