I was thinking of getting some kind of prepaid Visa/Mastercard. But the Coles prepaid Mastercard PDS states you cannot use it to setup direct debits or make regular recurring payments. I want to pay an overseas site once every six months, but don't want to provide 'real' credit card details in case they're hacked.
Where can I get a prepaid Visa/Mastercard type card to pay them once every six months?
You can probably use the Coles prepaid card - you wouldn't be setting up a direct debt - they would just be keeping your card details on file and using them every 6 months.