The BS EN228 specification already incorporates both premium and super unleaded grades. For both grades, with regards to ethanol, the two "E" sub-specifications in fact relate to 2.7% and 3.7% max oxygen content fuels, with maximum ethanol limits of 5 and 10% respectively.
The labels on forecourt pumps form part of the spec. E5 doesn't necessarily mean 5% ethanol - it means the fuels conform to the 2.7% maximum oxygen content specification which amongst other parameters, allows for any ethanol content between 0% and 5%. E10 means 3.7% oxygen content with any ethanol content between 0 and 10%. It was deemed that E5 and E10 labels would make things easier to understand
The fact that super unleaded used to be largely ethanol-free but now largely isn't is not due to refineries closing - it is a shift from alternative bio components such as from ETBE to ethanol due to a "sustainability index" (SI) now incorporated in fuel mandates. ETBE generally has low SI, Ethanol can have a high SI depending on manufacturing process and feedstock source.
As for the earlier question about the affect of removing ethanol (which can indeed be done by water washing), the residual fuel will have a significantly lower octane. It will also be very likely to be somewhat corrosive (as metal deactivator additive will also be removed by water washing)