where does it say it has an Octane rating of unleaded 99? is there any signage or branding at the petrol stations that says this?
Maxol E5 is advertised as unleaded 99 so that be the best fuel in Ireland(apart from E85, which requires conversion kit to run), maybe applegreen is 99 too, but make no mention of the octane rating of it. maybe they cant guarantee the consistency of the fuel to sell it at 99. Most fuels in Ireland at this stage have 5% of ethanol, with all companies required to have it in their fuel by the end of this year
I wouldnt really worry about it too much in a normally aspirated altezza different story if you have a turbo