stick to it?
print notes, then why not, at the same time as issuing them with that license, make those notes "legal tender" (which they more or less are anyway!). Either that or make them produce the notes idealistically to the Bank of England ones.
I meant both.
I accept that a shop could refuse some money BEFORE a transaction. But if it's payment for a service which has ben completed, or something you cannot return (like petrol), then thye should have to accept all legal tender.