I am guessing you are in the Americas, if that, what is the shipping to UK and how much do you want for each?
I'm asking for 20 usd on ebay. If you grab all 12 I'll give them to you for 200 usd. I'm not sure on the shipping, I've never shipped outside the U.S. before. Pm me your address and I'll look it up. Or if you want you could send me a label. My zip code is 32205.
In my opinion $20 per blade is quite a lot. Imagine, in the best case user can reach 50GHs per blade, for 55W (the lowest I have ever seen with that). It gives 0.0006285 BTC daily. If pay $0.1 per kWh to reach simmilar ROI to new S4, price should not be higher than $10 per blade. I do not tell about $ what user has to pay for p2102 device, PSU, cables, computer he has to use, abilities to make everything to work and so on.