You should have arranged for as much of the bond as possible to be paid from any entitlements such as annual leave. The bond paid is money paid in order to earn income. Claim it on tax. Don't ask for an independent ruling, if they come back with a no, then it is game over. If you make the claim and are audited some time in the future then at worst, you can argue that you thought the claim was justifiable and therefore not be charged a penalty, only any payment that the ATO thinks should have been paid in the first place. The chance of being audited is negligible and the claim is totally justifiable, more justifiable than half the claims made by various professions. If your accountant won't make the claim, find one that will.
I have done exactly this in the past and my claim was never disputed by the ATO. Once again, the last thing that you should do, ever and for any tax query, is get an independent ruling from the ATO.