"Looking at the requirements for a tax invoice (I've only ever asked for ABN/Date/Price) it's amazing how many businesses don't follow those guidelines."
May one suggest that you are not required to pay GST if you are not given a Tax invoice. I believe the onus is on the supplier to charge/collect GST in accordance with the prescibed system.
May I also suggest (based on a previous answer from you) that you do not pay hotel bills (or any other) without an itemised account. This is the same advise that I would give you if you came to me with a claim for expenses.
