Apologies for resurrecting an old thread.
Minimal miles still being done here and E10/E5 are now widely available.
XC40 T3, first fill up with E10, the thing sounds like a bag of bolts under heavy acceleration – not AWFUL – I notice it but my wife doesn’t. Possible loss of a small amount of power too but I’d expect that.
Next fill up, tried E5 and the engine is back to normal. Filler cap has E10 and E5 labels as I’d expect on a 69 reg.