You could tell Council simply to tell the muppet that as it's an airfield, and aviation fuel that they have requested further information from CASA and they expect a reply within the next 12 months. When he enquires in 11 months time for CASA's response they can reply that all the rules have changed and they expect a reply in the next 12 months.
He MIGHT just get the idea that they aren't interested.
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On a lil more serious note.
Truck doesn't have to be registered as its on private property.
However it prolly needs some form of insurance, whether on its own or under the airfield or drop companies cover.
Being a fuel dispenser, it prolly needs checking for accuracy/OH&S.
You already have your EPA docs.
Do NOT give copies of these docs to council, but invite them to inspect them. Having copies of said is none of their business.
They can then write the complainant a nice letter stating that they made enquiries, viewed all relevant documentation and have no problem/jurisdiction. If the complainant thinks otherwise, they can ask him for similar documentation for any fuel container and related dispensing equipment he has on his property...right down to the 2 litre fuel can that he has for his whipper snipper!