I have run my 1980 UK +8 3900ccs on RON 93 10% in the USA (that's Europe (97/98) with out issues for 4k miles. Also in mainland Europe on 10% Ethanol for many thousands of miles. In the UK I use whatever 98/99 is available usually supermarket including Tescos. I do the same for my AMG Merc GLE43 and that runs happily on whatever it's filled with.

1980 +8 Blue
And a few others
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Stephen