There is a proper old fashioned bike shop in Leicester, he is meant to be one of the best wheel builders around, old guy, he does bike, motor bike, classic car wheel builds,
The shop is called Bob Warner cycles, its a real `Arkwright's' shop, I bet if you found his number and rang him, he'd either have some, or tell you where to get them.
I doubt he'll do posting, as he's proper old, but if he's got what you need, I'll go pick them up and mail them to you.
Mark