Well, as I suspected, the problem was with their supplier (distriread UK), which had Elonex devices in inventory but erroneously listed them as Irex's.
Pickabook have offered me to refund my original purchase price, plus shipping of sending the device back to them.
So all is well. Except that I still am without a dr800...
There's something I still don't get though; Mine was not the first erroneously listed device that they sold, and yet mine seems to be the first complaint they received. So why did the previous buyers say nothing ? Didn't they notice they weren't shipped what they had ordered ? What's wrong with people ?!