Thx Dimelow, I've contacted Ms Suzanne and she said that the bulk of applications should be causing the delay. And yes, sal paradise, we could see what documents are still required.
The problem is that my personal referee and my academic referee 1, who is the same person, sent the references directly to Cambridge more than a week ago. I've called the BGS, and they said that the remaining documents have arrived. BUT, after that acknowledgment, only the academic reference 1 was deleted from the list, and the personal reference was still there. That puts me in doubt of the confirmation. I don't even know if my application is being considered now!
As for the photos and cover sheet, I've called the BGS and they asked me to send 4 copies. I've sent 4 photos as well, 3 glued, and 1 unattached just in case.