AFAICS GA is a much smaller thing in Europe, and European regulators have largely taken a lets wait and see attitude, and will presumably follow whatever the US

AFAICS GA is a much smaller thing in Europe, and European regulators have largely taken a lets wait and see attitude, and will presumably follow whatever the US counterparts will end up doing. 100LL is very expensive in Europe, and thus there has been more interest in diesel piston engines.