If I had a Broomstick 2 details

A boy sits on a broomstick and flies high over a fantasy land of tall stone houses by the sea, He does not appear to be steering the broomstick: this is the sort of fantasy where you don’t have to do any work, but jest get carried along for a ride, but you don’t win any Quidditch games this way! There is an elliptical border of flowers surrounding the picture.

I had difficulty reading the signature of the artist (or engraver, or both) but I think it is Harry Clarke.