There's 10 year old zeds in Ireland that would have only ever been run on standard unleaded. Yet on this forum it's regarded that after a few months the engine will be blown to 1000 pieces.
So either that is not true or it's due to the ethanol content of Irish fuel.
"The BOS Scheme places an obligation on suppliers of mineral oil to ensure that 6.383% (by volume) of the motor fuels (generally Gasoline and Motor Diesel) they place on the market in Ireland is produced from renewable sources, e.g. Ethanol and Biodiesel. The obligation was increased from the 1st January, 2013. It was previously 4.166%"
Supposedly this equates to our standard Irish unleaded being higher than 95 RON.