I'd disagree with that. Any motor spirit containing ethanol would be poor quality motor spirit.
The good stuff is very hard to find these days.
Peter
Bit of a thread drift, but..
I'd be inclined to agree with you (ethanol mixes are still not permitted to be sold here in WA) but I believe that the term "good quality motor spirit" is so open to interpretation that no one really knows what it means.
Does it relate to freedom from sediments, water or what ???
We did use some "good quality motor spirit" many years ago in an old J1 Auster and ceased very quickly after we were plagued by fuel starvation issues caused by vapour locks.
Went back to good old Avgas VERY smartly and never had any further problems .