80's movie

It was about a mom that was in the circus. She had two kids a boy and a girl. The family had to move in with there grandparents or something like that. The kids get visited by some fantasy creatures (one was really hairy) come and take the kids to another universe. There was a Queen that was part butterfly and a king that was a little person. At some point the kids where banished down a slide.

Anyone know this movie the title was something like " land of the little's"

Could it be The Great Land of Small?

Yes you are the best this has been driving me crazy for years!