So close yet so far away

We've just been told that our interim occupancy certificate cannot be issued because of the fire safety requirement set by the Building Code of Australia. According to section 3.7.1.3 of Volume 2, the external walls of the building must be at least 900mm from the allotment boundary. Since our land is made up of multiple lots, the house is sitting right across one of the internal boundary (between Lot 29 & 3). Therefore, a lot consolidation is required to remove the internal boundary.

Lot 29, 30 & 1

I went over to the Land and Titles office and was told I'll be needing a surveyor to draw up the plans before I can submit an application. The application fees are roughly $1500, but I have no idea how much the surveyor will charge for their work. Even worst is the time frame, the approval process can take 3-4 weeks and this estimate doesn't include account for the time taken by the surveyor. 

So the bank will not release the funds for the final payment pending occupancy certificate, and the handover that's scheduled for next Monday will likely be without keys. If only we have been informed about this a lot earlier, we could have had the lot consolidation prepared. As it stands, our only option left is to come up with the funds for the final payment ourselves. Then, once we have occupancy certificate, we'll have to chase up reimbursement from the banks.