Thanks all for assistance with this, I now have it working.
I think part of my issue was after originally installing filament a few days ago, I ignored an 'npm run dev' error which stated 'dev' wasn't an available script. Turns out I didn't have a 'vite' setup, or a 'tailwind.config.js' file. Not sure why this was, maybe because my project is a couple of years old and was originally built on Laravel 10 (maybe 9) before upgrading.
Anyway, after setting up tailwind and vite, and running 'npm run dev', inclusion of these colours started to be recognised and working.
:wq