Of the set, the second part is a major project, a double page spread.
The brief went something like this: Allow for a text area taking up about 1/3 of the left hand page. Sebastian is seen to either build or find an imaginary world under the kitchen sink. Make it detailed with a cartoony edge, and use good contrasts of scale. Allow a 30mm border between the trimmed edge of the page and the start of the text. The text was not supplied.
Here's the layout idea from my sketchbook:
Now to begin the watercolour work. Masking fluid first. For this part it was easier to take photos rather than scans. I started with the browns and beiges.