Thanks for your input guys.
I can't imagine that any of those above are originals but then he has some listed at the moment which look a lot more authentic. Here's some links:
http://www.ebay.co.uk/itm/ADAM-HUGHE...QAAOSwpP9Y6NEt
http://www.ebay.co.uk/itm/MICHAEL-TU...4AAOSwc49Y6NSY
http://www.ebay.co.uk/itm/MICHAEL-TU...0AAOSw3utY6NM0
http://www.ebay.co.uk/itm/JACK-KIRBY...UAAOSwnF9Y6AFC
I can't say much about the kirby sketch as I'm not a close follower of his art.
One thing that looks suspect with that last fathom sketch is the white border around the image: It's as though he's printed the image off on paper that's larger than the image (hence the white border) and then done a bad impression of Mike Turner's signature to make it look legit.
Wonder what he'd say if asked if the pencil could be rubbed off or not. I'm guessing he'll have an answer like it's been sealed.
Guess if it's too good to be true then it is. Just annoys me that, assuming he's selling copies / fakes that people can get away with this so easily on eBay. There's obviously plenty of people out there who feel like they have a true Turner piece when they really don't; that poor owner of the Supergirl pic for example.
[B]EDIT: Confirmed by Aspen comics themselves that the art this guy is selling is FAKE.
DO NOT BUY FROM THIS SELLER.[B]