It's hard to compare the price of gas between the US and UK. The tax structure for it is pretty different. Same for other states.
E85 is something I wouldn't touch with a 10' pole. Even if my vehicles could run it, it just doesn't have the same energy potential.
But if it works for you, go for it!
Actually a higher octane & produces a few more HP! Burns hotter though so that is why I don't run it every tank! My friend uses it every tank 3 years running with no issues!
Ca. has the most expensive gas in the nation! The cheapest low grade gas here is about $3.65 a gallon! I'm glad my truck can burn E85! Lucky you guys!!!