If its Bournemouth, they have a tent for 'unentered dogs' at the entrance to the show. Its run by a rescue charity (usually Welsh Springers I think) and costs about a fiver to put your dog in there for the day. They will look after it and exercise it if you want them to or you can come and go from the show to see to it (only a few yards from the entrance). You don't need to book just turn up on the day. Take a cage for your dog so its secure or a benching chain if its used to being on one, although I doubt it is, so a cage would be a much better bet. Don't forget a water bowl (they will have them if you do forget). Your breeder can come out with you to see her and you can exercise her in the car park which is in a field in the New Forest - just take care of the ponies wandering loose! Its free to enter the show, but £5 for the car park. You definitely would not want to leave her in the car, they check the car parks and make announcements for any dogs left in to be removed.