We were in DV last week and we had not visited since May.
We asked at the gatehouse for our post and could only find one electricity bill. We tried to ask for the IBI bills, but the security guard did not understand.
We decided to try again the following day when a different guard was on duty. At first we were given the same pile of post to check through and found no further post for us. However, as we went to leave the guard asked if we were owners. When we said yes he took a pile of post from the back of the desk under the window. Behold - it was the pile of IBI bills, so we managed to collect ours!
My advice would be if no luck the first time try again when there is a different guard on duty and make sure you say you are the owner. The IBI bills seem to be in a separate pile from the rest of the post for your block and some of the guards are not showing this to you.
I hope this helps.
Regards
Michelle