Okay, here's the deal: Fans were not promised a photo and autograph. This event was not a meet 'n' greet for anyone. This even was so Gaga could arrive at Harrod's, go inside, and hang out with 50 lucky fans who managed to obtain passes to the Harrod's perfume event. The thing outside was simply a spectacle.
This is what I can't stand about Monsters, most of them are so entitled. If you wait 40 hours for a celebrity and they don't stop for you, that is your problem, not theirs. Gaga did not ask you to come to the event early. Gaga did not promise you anything. Gaga simply said she would be at Harrod's for her perfume launch. Nothing more, nothing less. She did in fact stop for a few fans, however, but there were thousands of people there and it's common sense she wouldn't have been able to stop for everyone.
Thank you for the updates, OP, you're one of my favorite Gaga stans.
they'll get over it. Did each and every one of them expect to have a conversation with Gaga, a photo and an autograph? 
They look tacky tbh.