
As Lucy says the owner should be able to get a duplicate copy from the Kennel Club . The Kennel Club is the only genuine Register of Dogs and if the owner tells you he is registered with the Dog Lovers registration or any other rubbishy registration - walk away .
Is the Staffy a pup or adult ? Do you know the parents - have you seen them or had any information about the parents. It is possibe the owner has a problem dog ( not necessarily but possible) and I would not advise a novice owner to take on a problem dog , especially a Staffy . :(
Call his bluff and tell him to give you as much info as possible re: the pedigree and you will contact the KC yourself - then see what he says .
Lesley