Cheers all. Must admit, I was pretty happy with it
It also goes to show that even a rank amateur can achieve decent results with the right tools. My Silhouette Cameo vinyl cutter makes this very easy - certainly easier than when I tried to create a Moshi Monsters shell for my son using liquid mask and a scalpel - looked OK from a distance, but close up was a bit rough. With the vinyl cutter it is muuuucccchhhh easier. And it will convert jpegs to a mask - superb!