Now we'd worked out better angles for the film I started thinking about the colour palette, the plan is to use greys and browns to show the oppressive atmosphere on the ground.
The mid (sky) shots are to be brighter, to show the escape from such a place and finally we decided to use bright, contrasting colours in the Imp's world to show excitement and playfulness.

So here's a 15 minute sketch to indicate the colours of the barrier and buildings