
You have the wrong forms I think I was talking to a lady recently who shows two Racing Greyhounds(one I think was placed at Crufts)& so you must be able to do so under the KC Rules & Regs (on page 3.25 of the R & R)B14
<Dogs Already Registered-A dog already registered with another Organistaion within the British Isles recognised by the KC may be accepted for registration on to the Breed Register Copies of the appropriate registration/transfer certificate & official pedigree issued by the relevant Organisation should accopany the application. Dogs so regostered shall be named in accordance with Regulation B10>(which says you must use the name the dog is registered with & you can add an affix & another word if the registered name is just one word)
So you will need the NGRA docs & the right KC form Might be would ringing the KC & having a word with them