A very good post Kevin, well done. And an admirable stance to take.
Sadly it appears the airport operator has overstepped the mark on this issue. It is not for them to dictate what people put in their fuel tanks. It simply does not fall in their remit. If it's accurate that this is the result of lobbying by TLC then it is very poor, especially by someone who purports to be an aviation person.
Make no mistake ABC this is a safety issue. Some engines are not designed to run on Avgas.
Perhaps the MOR culture so prevalent at Oban in the past could be put to some use now. 'Safety at risk to keep the fuel supplier's cash rolling in' might be a suitable heading.
Hopefully common sense will prevail.
I have previously had sympathy for the airport. Not a lot but some. The whole runway debacle, whilst initially their fault, could have been resolved quickly were it not for the aero club and TLC. However they have no defence on this issue.