“Charming” is a bit deceptive as an adjective, and using it here is not meant to damn the book with faint praise: it is a subtle expression of loss seen through the eyes of a little girl and her relationship with her grandad. As Grandad reminisces about the partner he lost she thinks about the camper van and how to bring precious memories to life.
The wonderful thing is that we are not told a moralistic story about the two grandfathers, and the little girl just accepts that grandad’s partner was a man; it just works as a story about memory and loss.
Bravo.