AJ,
FS numbers really don't match up properly to WW2 naval paints...
Hornet was wearing Measure 12 Mod., consisting of 5-N Navy Blue, 5-O Ocean Gray, and 5-H Haze gray. Her decks would be Norfolk 250 flight deck stain, and horizontal surfaces would be 20-B Deck Blue.
Hornets' hull had the two darker colors, 5-N and 5-O, while the island carried the lighter colors 5-O and 5-H.
Since you're in Australia, your best bet is to contact Sandle Hobbies and order the White Ensign Colorcoats from them. Otherwise, you can order directly from WEM in the UK.
Regards,
Jeff Herne
Modelwarships.com