Options??
You say you have to buy it from a new supplier. Is this because the airport have decreed this or because they are the only company left supplying fuel once Esso leave??
Have you thought about talking to the fuel supplier who is leaving and "doing a deal" for an Avgas tanker and a regular supply??
As well as the major players (Exxon, Shell, BP, Total), there are independents out there who supply the smaller airfields.
What about Total's unleaded avgas?