You haven't missed that, Rob, because I completely forgot to share, but I'm quite intrigued.
The only place I've seen these online previously is Kesgrave (for those that don't know, Kesgrave is one of the bigger Ebay merchants in the UK, Suffolk), and they currently have them up for £8.95 each or 10 for £75, plus carriage at £7.50.
I just happened to search Ebay for "dennerli" (this being part of the scientific name Caridina Dennerli), and another listing popped up, someone called Smudger1976, whose location was also listed as Suffolk. I assumed this was probably someone who had previously bought from Kesgrave, and had bred them.
The listing was 5 for £9.99 + £9.00 carriage, but it was an auction listing, not a Buy It Now. I thought I'd whack in a bid of about £20, which I did, and was instantly outbid. Upped it to £22, and was leading for a while, until about 12 hours to go. The initial bidder was then outbid to about £30 when the auction closed. I wasn't going to go that high, so thought nothing more. That evening, I had a Second Chance message from Ebay, accepted, paid, had a brief "When do you want them" email convo with the seller.
Box arrived yesterday - the sender's name on the sticker on the box is Kesgrave. Not quite sure what to make of that. My only thought was that Kesgrave had too many of them, wanted to sell them cheap, but didn't want to lower the "official" price. The seller has nearly 4500 feedback points, 24 since January 2013, a few in early 2012 and then everything before that seems to be 2010 and previous.