Someone please put me out of my misery.  I apologise for this.  This is one of those weird thoughts that pop into my head in the middle of the night!

EG.  A puppy was born on 10 December 2007, s/he will be 12 months on 10 December 2008.  Can he enter the puppy class in the show presuming that the rules are the usual, min. of 6 months not exceeding 12 months on the first day of the show etc. etc.

Yes it's fine

We had a pup born on 3rd July 2007, SWKA started 3rd July 2008, our day was 4th and we were still in Puppy. - I checked with show sec and on here!!

Does that help?

Agree, that is fine, the rule is not exceeding 12 months and providing the dog becomes 12 months on or after the first day of the show then no problem.

Thanks for that, probably find there's only a junior class in the end anyway :-D but good to know for future reference.