Have just Googled "Eldorado" wine, but most hits were for the El Dorado vineyards of California, which I am sure produce far better wine. There is now also a Scottish tonic wine, complete with saltire label, called Eldorado: similar to the Buckfast Tonic wine produced in Devon, but so much imbibed by those who like a fortified wine! Not the same, I think, as the Eldorado "plonk" we used to get back in the 60s/70s in red, white and rose.