It's a pain in the arse! >.< Usually my Bank will decline GAME UK payments when they're multiple like that, which is why I changed to In-Store group buys. This time they haven't though...
What I have been told though, when I eventually got through to their CS (30min wait), was that the orders I had made had been charged multiple times each, but most of the charges had been refunded, all bar 4 of them! >.< Not very impressed as it has no ties up my funds in my bank account, so should I need any money from it, there's not enough "available" funds...