http://www.guernseypost.com/news/article/?id=28 that has some info and a link to another site, that doesnt seem to be working right now.
They do look quite nice though
Edit: that site I linked to says "They will not be on sale through Guernsey Post outlets or available to order."
but that seems a bit silly to me, surley selling them outwith the circuit (they're avaliable at Brands this weekend) would have a far greated benifit for his charity, hmm - perhaps i've misinterpreted though.