I post this to try and be helpful, not
I registered online a month before I visited G2, upon arrival my statement that I had registered online was met with a shrug and I was told there was no point because I had to show id anyway and I may as well give them the details there and then. It didn't bother me because I was the only person at reception, but I thought I'd warn those who are hoping to avoid queues/save time on Saturday by joining online.