Barney had one and I remember starting a thread on here in sheer panic.
My friend actually found it, Barney's wasn't apparent unless he was stood up. I took him straight to the vet, she said sometimes its possible to push them back up and they stay up of their own accord, but Barney's wouldn't push up at all.
His was repaired when he was castrated. It didn't cause him any problems prior to having it done, and none since.
I really wouldn't worry, just keep an eye on it just in case it changes at all but I can honestly say (and this is from the original and worst Miss Worrywart) there really isn't anything to panic about.
Show dogs must have no hernia or repair as far as I know (probably wrong but just something I remember reading).
I believe that to be correct Debbie, or at least thats what I was told.