so im guessing that a new card issued outside of the main fuel suppliers wont work due to the acceptance? i.e if visa, amex, mastercard tried to issue cards they wouldn't be generally accepted by the supplier?
Why wouldn't they? We carry a wad of fuel cards on each aeroplane only two of which are issued by petroleum companies (Shell and Air BP). All the others (UVAIR, Petrofer, and all the others that I don't remember because I rarely use them) are some sort of specialised credit cards. So I don't see any reason why an "Air Mastercard" should not be accepted - after all, every fuel supplier happily accepts a normal Mastercard.