William Trundle, the main character in The Christmasaurus by Tom Fletcher, is a wheelchair user.
From the publisher:
The Christmasaurus is a story about a boy named William Trundle and a dinosaur, the Christmasaurus. It’s about how they meet one Christmas Eve and have an extraordinary adventure. It’s about friendship and family, sleigh bells and Santa, singing elves and flying reindeer, music and magic. It’s about discovering your heart’s true desire, and learning that the impossible might just be possible…
UK publisher: Puffin (2017)
US publisher: Random House Books for Young Readers (2018)
Author represented by: Stephanie Thwaites of Curtis Brown