"Solved"

The solution that worked was:
.1. Create a new workspace on the client machine and feed it from my dev machine.
.2. On the client WebApp machine "Create a New Web Application"

That solved the problem right away.
Firefox stopped saying it could not load applicaiton.css and my rows a properly coloured based on what is in application.css

Hence "Solved"
Thanks for your thoughts.
Archie