Now more confident in my design after the Paper Prototyping I was able to take time to create a prototype in Flash.
With this I was able to start testing interaction in a more realistic situation, with the benefit of being able to work with a touch screen also.
Run the Flash Prototypes (warning, they're flash).
With the interaction refined (and the decision that the green was a little too much!) we could move onto refining the visual treatment and building the...