Can anyone please explain what a breeding endorsement is.. Thanks

its something a breeder has added to the kennel club registration to stop the new owner being able to register any progeny by the dog/bitch theyve bought/

This is normaly done by responsible breeders who wish to ensure the quality of their breeding line and hopefully to discourage the new breeder from breeding without doing all the rtesearch needed.

Of course it can't stop them being used for breeding, but does stop the resulting pups being registered,and prospective new owners being fooled into thinking theyhave a great pup with a great pedigree, wheras the mating may have been totally unsuitable, or the bitch (or dog) not of breeding quality.

The breeder must make puppy owners aware of this endorsemetn and get their signature to confirm this.

The endorsement can be lifted if the owner shows the breeder that they will make a responsible breeder and guard the quality of their line, and of course can ensure theat the bitch is old enough and has had all the relevant health tests.

In addition to what the others have told you-

Breeding endorsements are usually backed up by a contract of sale stating the requirements of the new owner in order for the endorsment to be lifted.
Endorsements are not always removable often breeders place endorsements on slightly sub-standard puppies i.e mis-marks ect to prevent them from being bred from.
breeders also endorse puppies to protect a line they are breeding and dont wish to be out crossed and there may not be a suitable dog in this country to use on the line!
in both cases the breeder will choose not to lift the endorsement.
when buying a puppy from which you may wish to bred it is vital you must make that clear to the breeder,you must also draw up a mutually acceptable contract and both sign it and keep a copy.
i hope this helps
:)