I was having a look through Bunnings the other day and you can...

I was having a look through Bunnings the other day and you can buy a small fire proof safe that you can bolt into the concrete slab of your house, if you have a slab. The bolts are done from the inside of the safe and so are not available to be cut from the outside. These safes range from about 200 to 500. Keeping your PM in a safe storage in a bank or someplace similar is probably better but that will cost you as well.