I got the refund on my visa card after returning the Odyssey, althought the £12 cost to courier it back to the shop was send in the form of a postal order — I probably haven't seen one of those since xmas 1980.
I was amazed to see it back on the CC website for sale, but now there's the caveat that one key doesn't work, but no reference to the issue I experienced. I doubt the issue I found has been fixed if there's now a dead key (I certainly didn't find a dead key in the couple of days I had it) — surely if a tech has fixed and serviced it all the keys would be working. Oh well.