Update,
Just finished re-painting my clamshell from the new Tak duck egg blue? (back to Tak green.)
Came out better than I expected using just a dippy dab method with some tamiya modelling brushes I had. The young lass at Bunnings did a great job at colour matching as well! Just used scotch brite to ruff the surface for a good bond and a good clean afterwards. I was also able to maintain the textured finish as well.