My Prisma's have arrived, although I think they may actually be seconds. Out of 72 loose pencils I had 3 which had completely smashed cores, and a further 8 had no writing on the barrel so I can only guess at the right colour, and there was one which only had half the barrel and the core. Anyway, I emailed the guy and he has agreed to refund a sixth of what I paid, so I have ordered replacements from 1Buy1Pencils, which is where I purchased the sharpener and paper stumps which also arrived today.
So I have them all sharpened, I nipped out to Asda this evening to get some baby oil and as soon as I have a bath I'll go try them out and let you know how I get on.
I've had a bit of a think about it and discussed it with my good chum Mar and my wonderful other half Graham, and I've decided to return the pencils for a refund. I bought them on the understanding I was buying quality pencils, when in fact it looks very much like they are seconds. So I'll just have to wait a wee bit longer :(