I have just got the Thames Valley Mog mag & there is an article on E10 fuel. BP claim it doesn't cause corrosion & is in fact better that E5. It also suggests if you have used E5 there is no risk from E10.
Mind you Mr BP also says unleaded doesn't cause valve seat recession.
He does point out that cheap fuel may be cross contaminated as the road tankers aren't dedicated to one fuel e.g. diesel in petrol. I can confirm that can occur with solvents for ink so I see his point there
