Re tax deductibility of card fees: According to the ATO in most circumstances they are --
ATO on card fees
That's not actually what that ruling says - the ruling says you can tax deduct your card fees
to the extent that they relate to paying a tax liability, in most circumstances, or if it's used in the course of carrying on your own business, to the extent that it's used to carry on your business. The tax liability circumstance also comes with a giant "and you did not borrow money from your card provider to make the payment" caveat.
In other words, IF you pay a tax debt (not including fines or penalties) using your card, and you did not borrow money to do so, you can tax deduct the proportion of the card fee that relates to paying your tax debt.
For example, if you had a card fee of $100 a year, paid a tax debt of $5000, and spent $15,000 on the card on personal expenses during the year, you would be entitled to tax deduct $25 - but only if you didn't go into debit to pay the tax debt, i.e. your account balance would need to be in credit or it would need to be a debit card.
If you're using your card solely for your own business (and you have to be carrying on a business, not an employee paying business expenses) then you should be able to tax deduct the whole thing.
Otherwise, your card fee is NOT tax deductible.
Note: this is not legal or financial advice, YMMV.