Vanessa, when you buy a puppy the breeder will give the new owner the KC transfer papers, the breeder pays £12 for this at the time of puppy registration with the KC, most good breeders will also order from the KC a 5 generation pedigree at a cost to the breeder of £6.
This gentleman would most certainly have been given the KC transfer papers and possibly the pedigree from the breeder FOC,
The new owner then sends off the transfer sheet for a cost of £12 to have the pup transfered into their name, they can order a pedigree if they don't already have one at the same time.
It may be possible that the original breeder did not give a KC pedigree, but most certainly would have given a KC registration form. If this gentleman has posted it off for change of ownership, perhaps playing devils advocate this is why he has no paperwork at present. It takes approx 7 days to have the pup transfered and new paperwork returned.
If this were the case, then you could wait for the transfered paperwork to be returned before taking the pup, he would then need to sign it and pass it over to you, you would then post it off yourself with £12 to register the pup into your own name and you can order a pedigree at the same time.
The man in question can not charge you extra for this, you have to do it yourself once you have the transfer paper.
If there is no KC transfer, don't touch the pup with a barge pole, it may be stolen or unregistered to start with which can lead to bad temperament and health issues.