I know it's more money, but I would suggest biting the bullet and paying for packing inclusive service. They will isolate the things that MAFF might want to secondarily inspect, coordinate all the reporting and paperwork, pack here and unpack there. Should include insurance as well.
If you pack it they will not insure you for damages and MAFF may hold your things for longer because of difficulties finding those hiking boots they want to inspect for dirty treads.
I've done it both ways. Packed by them is definitely the way to go.