However unused sheet-lets should not be available, so where have they come from? I can only assume that they have been left over from the original trials.
Officially these should only appear as single stamps, used , affixed to a cover. They were only available for the Special Delivery Trial that took place in High Street, Camden Town last year.
I checked out the seller who says "I will be adding the stamps as I can get my hands on them. They are now really hard to find but I will do my best to find some more, but these may be the last stamps I can get"
I would like to say you seen it here first, but can not, thanks must go to Brian Sinnott who reported it on his website yesterday.