There's been (still is) a short but illuminating debate on E10 petrol in uk.rec.sheds but not, as far as I can see, here?
As someone who knows about almost nothing, is sceptical about almost everything, and who likes to see balanced discussions ... I'd love to see a debate here, given the wider, and often very informed, user-base of D-I-Y.
Cheers John
(Currently a diesel driver, but likely to move to petrol next.)