Long story short, ever since installing Windows 10 on my machine, my DK2 camera has not been operational. I presumed that it was an error with the USB hub. However, a couple of days ago, I emptied a full beer into my keyboard (Don't ask), and I since then replaced the G19 with a Blackwidow keyboard.
Since then, the camera now turns on as expected. Both keyboards are using the same port, with the Razer using an additional port for power. I can only presume that at this point, there was a conflict somewhere with the two drivers.