I have just discovered that when I had 2 of my girls chipped at the same time by my vet's they mixed up the numbers on the paperwork.
Subsequently when I sent off my owner reg papers they came back with the wrong numbers on them.
I have e-mailed the KC but not heard back, (I may have e-mailed the wrong dept).

Will I be able to get them corrected, will it cost me (or the vet's when I complain to them) and which department should I be approaching?

When I had to have my bitches microchip removed and replaced I just phone them KC with the new details, which were changed free of charge on their database. If I had sent my reg docs in they would have changed them, but it would have cost me £5 for the new document.

My bitch was microchipped and i sent off her paperwork, when she went back a few weeks later...no microchip! so she was re done and i just phoned up the KC to let them know- i did this quite a while afterwards and did it because of health tests i had done. They updated the database instantly and said for paperwork their would be a charge (the KC increased their charges as of 1st july)

Thanks for the info, I'll ring KC but if there is a charge my vets will be paying!

If it's just the chip people who need telling (you haven't included the details on KC registration database records yet) then you need to contact Pet-log or whichever chip database your chips are with. 

Obviously you need to do that anyway, but above answers seem to refer to the kennel clubs records, as when you register on-line and the certs come back you are then able to put the chip details in.

I'd expect teh vets to pay if they bobed.