I won't accept either because it simply does not sound like John. Those 'Aaahs' sound almost exactly like the opening to 'Lovely Rita'. Plus when you hear the link that Alan gave, it just doesn't sound like John's high pitched vocal in the song, its a bit of a lower pitch. I mean listen to the 'Version two - 5.1 mix rear left segment' after the 'aaahs', John starts singing and his voice does not match the 'Aaahs', the 'aaahs' are too deep and it sounds like Paul. I'm with Alan, I'm still convinced it was Paul.