Thank you very much, that article by Nationwide vindicates all I said.
Show me an "honest rate" if you ever find one. The rates given to me in my 3 examples were way off the Visa rates on the day.
You would have needed a crystal ball yourself to have predicted the falling interest rates together with the fact that it would take the airline several weeks to process your charge - unlucky there.
It's interesting to see that the bank acknowledging that malpractice is going on is Nationwide - who themselves don't impose an exchange rate levy on foreign currency transactions.
Although the Thomas Cook Credit Card I was using was operating without an exchange rate levy on foreign currrency transactions, but they're withdrawing that and imposing the usual levy next month or soon after - can't remember.
The only plus side for me is that it's only happened to me so far in Australia, it's been fine in several other countries.
Incidentally, when I arrived at Cairns Airport and tried to use the airport ATM with my current account debit card, the airport ATM tried to force me into accepting an unfavourable exchange rate and when I refused the rate it declined to give me any cash so I waited until I got to a regular ATM on the street. I guess that's the next big con - ATM's trying to profit from fixing an exchange rate at the time of cash withdrawal - in fact, I understand that's a widespread practice in Spain.
So my big question is, if retailer's are failing to obtain the credit cardholder's consent and the banks know about it, then why isn't something being done to protect consumers from this malpractice?