
Oh dear I have two who do not do indoor shows, they turn into boring little robots that cannot wag their tails, where as outside happy & waggy, good job the two young ones will show anywhere
You will have to do some basic obedience on grass so it loses it's novelty & he gets used to it just being another surface to walk on
A lot of indoor trained obedience dogs have the same problem early in the seaon until they realize that they are expected to work on their"play"surface as well