Couldn't resist throwing a bid in on the red one in the end and was pleasantly surprised to win it for about half the price of the blue
It arrived today and, as suspected, is basically identical other than being clear red instead of marbled blue - from the identical matrix code, I assume it was pressed from the same plates.
The only other difference was that the red one also included a double-sided insert on glossy paper which has the same images as the inner sleeve on official copies. I'll sort some pics out over the weekend.